Sharon is saving for a new phone. She starts with $42 and earns $15 each week from her parents. How many weeks will it take to save a total of $207?

Answer:

x = 20

Step-by-step explanation:

if a line is parallel to a side of a triangle and intersects the other two sides, it divides those sides proportionally.

QR is parallel to ST and intersects the other two sides of the triangle, then

[tex]\frac{PQ}{QS}[/tex] = [tex]\frac{PR}{RT}[/tex] ( substitute values )

[tex]\frac{x}{45-x}[/tex] = [tex]\frac{16}{30-16}[/tex]

[tex]\frac{x}{45-x}[/tex] = [tex]\frac{16}{20}[/tex] ( cross-  multiply )

20x = 16(45 - x)

20x = 720 - 16x ( add 16x to both sides )

36x = 720 ( divide both sides by 36 )

x = 20

Answer:

To simplify the expression (-3+1)+(-4-i), we can perform the addition operation within the parentheses first:

(-3+1)+(-4-i) = -2 + (-4-i)

Next, we can simplify the addition of -2 and -4 by adding their numerical values:

-2 + (-4-i) = -6 - i

Therefore, (-3+1)+(-4-i) simplifies to -6-i.

Step-by-step explanation:

By using this value of x in the formula we previously discovered, we can get the patio's area Patio's size is equal to x2 + 4x + 4 = ((1 + 7)/3)2 + 4((1 + 7)/3) + 4 = 4.72 square meters.

A square is a 2D shape with equal-sized sides on each side. The area would be length times width, which is equal to side  side because all the sides are equal. As a result, a square's area is side square.

Let's first find the area of the entire rectangle:

A = lw = (3x + 6)(2x + 4) = 6x² + 30x + 24

Area of patio = (x + 2)² = x² + 4x + 4

Area of herb garden = (2x + 2)(x + 4) = 2x² + 10x + 8

Area of flower garden = (3x + 4)(x + 4) = 3x² + 16x + 16

Sum of areas = x² + 4x + 4 + 2x² + 10x + 8 + 3x² + 16x + 16

= 6x² + 30x + 28

0.25(6x² + 30x + 24) = 6x² + 30x + 28

Simplifying and solving for x, we get:

1.5x² - x - 1 = 0

Using the quadratic formula, we find that:

x = (1 ± √7)/3

x = (1 + √7)/3

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The area in square meters of the patio is 850 square meters.

What is a rectangle?

A rectangle is a geometric shape that has four sides and four right angles (90 degrees) with opposite sides being parallel and equal in length.

Let's start by calculating the total area of the rectangle:

Area of rectangle = length x width = 100m x 40m = 4000 square meters

Now, let's denote the width of the herb garden as x meters. Then, the length of the herb garden would be 10 meters.

The area of the herb garden would be:

Area of herb garden = length x width = 10m x x = 10x square meters

The area of the patio can be calculated as:

Area of patio = (100 - x) x (40 - 2x) square meters

(100 - x) is the length of the patio, and (40 - 2x) is the width of the patio, since the herb garden takes up x meters of the width.

The area of the flower garden can be calculated by subtracting the area of the rectangle, the herb garden, and the patio from each other:

Area of flower garden = 4000 - 10x - (100 - x) x (40 - 2x) square meters

Now, we need to find the value of x so that the sum of the areas of the patio, herb garden, and flower garden is 25% of the area of the entire rectangle. In other words:

Area of herb garden + Area of patio + Area of flower garden = 0.25 x Area of rectangle

10x + (100 - x) x (40 - 2x) + 4000 - 10x = 0.25 x 4000

Simplifying this equation, we get:

-2x^2 + 30x + 1000 = 1000

-2x^2 + 30x = 0

-2x(x - 15) = 0

Therefore, x = 0 or x = 15. Since x cannot be 0 (since the herb garden would have no width), the value of x must be 15 meters.

Now we can calculate the area of the patio:

Area of patio = (100 - x) x (40 - 2x) = (100 - 15) x (40 - 2(15)) = 850 square meters

Therefore, the area in square meters of the patio is 850 square meters.

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The antenna which is having an angle of elevation 71° from the front of the it is on is 19.67 feet tall to the nearest tenth of foot.

The angle of elevation is the angle between the horizontal line and the line of sight which is above the horizontal line.

To get the height of the antenna, we subtract the height of the building from the height from the bottom of the building to the top of the antenna.

we shall represent the distance from the point of observation to the building with x and the height from the bottom of the building to the top of the antenna with y. so that;

tan 68° = 125/x {opposite/adjacent}

x = 125/ tan 68° {cross multiplication}

x = 50.5033

tan 71° = y/50.5033

y = 50.5033 × tan 71°

y = 144.6722

height of the antenna = 144.6722 - 125

height of the antenna = 19.6722

Therefore, the antenna which is having an angle of elevation 71° from the front of the it is on is 19.67 feet tall to the nearest tenth of foot.

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On solving the question we can say that Therefore, the solutions to the inequality given inequality are: x < 4 or x > 6.

An inequality in mathematics is a relationship between two expressions or values ​​that are not equal. Imbalance therefore leads to inequality. An inequality establishes a connection between two values ​​that are not equal in mathematics. Equality is different from inequality. The inequality sign () is most commonly used when two values ​​are not equal. Various inequalities are used to contrast values, no matter how small or large. Many simple inequalities can be solved by changing both sides until only variables remain. But many things contribute to inequality.

two inequalities

4x - 6 < 10

4x < 16

x < 4

2x - 4 > 8

2x > 12

x > 6

Therefore, the solutions to the given inequality are:

x < 4 or x > 6.

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Answer:

9

Step-by-step explanation:

To find the answer to this question, we have to find 3/4 of 12

To do this, we need to do 12 divide by 4, then that answer multiplied by 3...

This means that she took 9 drinks!

Hope this helps, have a lovely day! :)

Answer:

9

Step-by-step explanation:

[tex] multiply \: \\ = \frac{3}{4} \times 12[/tex]

[tex] = 9[/tex]

Therefore, sally took 9 drink for her party.

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The mean, median, and mean absolute deviation MAD of the data are 15%, 10%, and 8%.

To find the mean, median, and mean absolute deviation (MAD) of the data, we need to first convert all the fractions to percentages:

Whitney: 16%

Chen: 8%

Bjorn: 6%

Dustin: 2%

Philip: 12%

Maria: 40%

a) Mean:

To find the mean, we add up all the percentages and divide by the total number of friends (6):

Mean = (16 + 8 + 6 + 2 + 12 + 40) / 6 = 15%

Therefore, the mean is 15%.

b) Median:

To find the median, we need to arrange the data in order from smallest to largest:

2%, 6%, 8%, 12%, 16%, 40%

Since there are six values, the median is the average of the two middle values: (8 + 12) / 2 = 10%

Therefore, the median is 10%.

c) Mean Absolute Deviation (MAD):

To find the MAD, we first need to find the absolute deviation of each value from the mean:

Whitney: |16 - 15| = 1%

Chen: |8 - 15| = 7%

Bjorn: |6 - 15| = 9%

Dustin: |2 - 15| = 13%

Philip: |12 - 15| = 3%

Maria: |40 - 15| = 25%

Next, we find the average of these absolute deviations:

MAD = (1 + 7 + 9 + 13 + 3 + 25) / 6 = 8%

Therefore, the mean absolute deviation is 8%.

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Compute P(x ≤ 15) = (15-10)/(20-10) = 5/10 = 0.5.

Compute P(12 ≤ x ≤ 18) = (18-12)/(20-10) = 6/10 = 0.6.

Compute E(x): The expected value of x is: E(x) = (a+b)/2 = (10+20)/2 = 15

Compute Var(x):The variance of x is: Var(x) = (b - a)^2/12 = (20 - 10)^2/12 = 100/12 = 8.33.

The probability density function is as follows: As the random variable x is uniformly distributed between 10 and 20. Thus, f(x) = 1/(20-10) = 1/10 for 10 ≤ x ≤ 20.Compute P(x ≤ 15):Thus, P(x ≤ 15) = (15-10)/(20-10) = 5/10 = 0.5.Compute P(12 ≤ x ≤ 18):Thus, P(12 ≤ x ≤ 18) = (18-12)/(20-10) = 6/10 = 0.6.Compute E(x):The expected value of x is: E(x) = (a+b)/2 = (10+20)/2 = 15.Compute Var(x):The variance of x is: Var(x) = (b - a)^2/12 = (20 - 10)^2/12 = 100/12 = 8.33.

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To determine the probability of a continuous distribution we use the integral to determine it and for the normal distribution the integral is not so simple, for that reason it is simpler to use range values from tables.

Probability can be determined from a continuous distribution in the following way:To compute the probability of a given interval for a continuous random variable, the area under the curve over the interval is determined. Integrals are used to calculate this area under the curve, which can be done either numerically or analytically using probability density functions.

For some distributions, such as the uniform distribution, calculating the area under the curve is straightforward. However, for other distributions, such as the normal distribution, it can be more difficult to calculate the integral analytically.

The normal distribution is a continuous probability distribution that is frequently used in statistics. It is defined by its probability density function, which is a bell-shaped curve with a mean and a standard deviation.

Calculating the area under the curve for the normal distribution requires the use of integrals. Integrals are difficult to solve analytically for the normal distribution because the probability density function is not simple. However, it is relatively simple to calculate the probability for a given range of values using standard statistical tables or computer software.

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a) The perimeter of square is 16 cm

b) The perimeter of rectangle is 18 cm

c) The perimeter of triangle is 27 cm

a) The perimeter of a square with side length 4 cm can be found by adding the length of all four sides. Since all sides of a square are equal, the perimeter is 4 times the length of a side. Therefore, the perimeter of a square of side 4 cm is:

Perimeter = 4 x 4 cm = 16 cm

b) The perimeter of a rectangle with length 5 cm and breadth 4 cm can be found by adding twice the length and twice the breadth of the rectangle. Therefore, the perimeter of a rectangle of length 5 cm and breadth 4 cm is:

Perimeter = 2 x (length + breadth)

Perimeter = 2 x (5 cm + 4 cm)

Perimeter = 2 x 9 cm

Perimeter = 18 cm

c) The perimeter of a triangle with sides 11 cm, 7 cm, and 9 cm can be found by adding the length of all three sides. Therefore, the perimeter of a triangle with sides 11 cm, 7 cm, and 9 cm is:

Perimeter = 11 cm + 7 cm + 9 cm

Perimeter = 27 cm

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The probability that a randomly selected quartz timepiece will have a replacement time less than 13.3 years is approximately 0.015 with a mean of 17 years and a standard deviation of 1.7 years.

To find the probability that a randomly selected quartz timepiece will have a replacement time of less than 13.3 years, we need to use the standard normal distribution formula which is as follows:

[tex]Z =\frac{X -μ }{σ}[/tex]

Where Z is the standard score

X is the variable value

μ is the mean

σ is the standard deviation

Given that the mean (μ) of the replacement times for the quartz timepieces is 17 years, the standard deviation (σ) is 1.7 years, and the variable value (X) we are looking for is 13.3 years.

Substitute the values into the standard normal distribution formula to get:

[tex]Z = \frac{13.3-17}{1.7} = -2.17[/tex]

Looking at the standard normal distribution table, we can find the probability of the standard score Z = -2.17 to be 0.015.

Therefore, the probability that a randomly selected quartz timepiece will have a replacement time less than 13.3 years is approximately 0.015.

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Eventually, the differential equation's general solution is:

y = y_h + y_p

y = c1e^(-2x) + c2e^(-x) - (1/6)e^(-x) + (2/3)

In the context of differential equations, the homogeneous solution of a differential equation is a solution that satisfies the equation when the right-hand side is equal to zero.

To find the particular solution of y'' + 3y' + 2y = 4e^x using the variation of parameters method, we first find the homogeneous solution of the differential equation by setting the right-hand side to zero:

y'' + 3y' + 2y = 0

The characteristic equation is r^2 + 3r + 2 = 0, which factors as (r + 2)(r + 1) = 0. Therefore, the solutions are y_h = c1e^(-2x) + c2e^(-x), where c1 and c2 are constants.

Next, we find the Wronskian of the homogeneous solution:

W(y1, y2) = |e^(-2x) e^(-x) | = e^(-3x)

To find the particular solution, we assume that it has the form y_p = u1(x)e^(-2x) + u2(x)e^(-x), where u1(x) and u2(x) are unknown functions to be determined.

We then find y_p' and y_p'':

[tex]y_p' = u1'(x)e^(-2x) + u2'(x)e^(-x) - 2u1(x)e^(-2x) - u2(x)e^(-x)y_p'' = u1''(x)e^(-2x) + u2''(x)e^(-x) - 4u1'(x)e^(-2x) - 2u2'(x)e^(-x) + 4u1(x)e^(-2x) + u2(x)e^(-x)u1''(x)e^(-2x) + u2''(x)e^(-x) + u1'(x)e^(-2x) + u2'(x)e^(-x) - 4u1'(x)e^(-2x) - 2u2'(x)e^(-x) + 4u1(x)e^(-2x) + u2(x)e^(-x) = 4e^x[/tex]

Simplifying and grouping terms, we get:

[tex]u1''(x)e^(-2x) - 3u1'(x)e^(-2x) + u2''(x)e^(-x) - u2'(x)e^(-x) = 4e^x[/tex]

To solve for u1(x) and u2(x), we use the method of undetermined coefficients and assume that they are both linear combinations of the exponential function and its derivative:

u1(x) = A(x)e^x

u2(x) = B(x)e^(2x)

Substituting these expressions into the previous equation and solving for A(x) and B(x), we get:

A(x) = -e^x/6

B(x) = 2e^x/3

Therefore, the particular solution is:

[tex]y_p = (-e^x/6)e^(-2x) + (2e^x/3)e^(-x)y_p = (-1/6)e^(-x) + (2/3)[/tex]

Eventually, the differential equation's general solution is:

y = y_h + y_p

y = c1e^(-2x) + c2e^(-x) - (1/6)e^(-x) + (2/3)

Therefore, the particular solution of the given differential equation y′′+3y′+2y=4ex is

[tex]y(x)=c_1e^{-x} + c_2e^{-2x} - 4 + 2e^{x}.[/tex]

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Answer:15 percent

Step-by-step explanation:

The correct answer is A. a-c+b-d=0. This is because when two sets of numbers are both negative, the result of subtracting the larger number from the smaller number will always be negative.

Subtraction involves taking one number or value away from another. It is one of the four basic operations in mathematics, along with addition, multiplication, and division.

When subtracting a from c and b from d, the result of either subtraction will always be a negative number. When the two negative numbers are added together, the result will always be 0.

The other options are not always true. In option B, ac > bd, this is not always true because when a, b, c, and d are all negative, it is possible for the result of ac to be less than the result of bd. In option C, a+c>b+d, this is not always true because when both sets of numbers are negative, it is possible for the result of a+c to be less than b+d. Finally, in option D, a/d < b/c, this is not always true because when both sets of numbers are negative, it is possible for the result of a/d to be greater than b/c.

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The correct answer is A. a-c+b-d=0 because the expression is always true when a, b, c and d are all less than zero.

Expression is a combination of symbols and operators that evaluate to a single value. It could be a mathematical equation, an arithmetic expression, a logical expression, or a combination of these.

This is because the expression is equivalent to (a-c)+(b-d)=0, which is always true when a, b, c and d are all less than zero.

This can be proven through a simple calculation.

Let us assume that the values of a, b, c and d are -1, -3, 8 and -4 respectively.

Substituting these values into the expression gives us

(-1-3)+(8-4)=0, which is clearly true.

Therefore, A. a-c+b-d=0 is the correct answer as the expression is always true when a, b, c and d are all less than zero.

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Answer:

The ratio of red to blue squares in the given set of 2 reds and 18 blues can be written as:

Red:Blue = 2:18

To simplify the ratio, we can divide both the numerator and denominator by the greatest common factor (GCF) of 2 and 18, which is 2. Dividing both terms by 2, we get:

Red:Blue = 1:9

Therefore, the ratio of red to blue squares in its simplest form is 1:9.

Wind speeds, represented by random variable X, have a lognormal distribution. The corresponding value of the standard normal random variable (Z) is associated with a wind speed of 14.35 is 25.5

Wind speeds represented by random variable X, in miles per hour, have a lognormal distribution. In other words, log(X) is normal.

If [tex]\mu = 4.8[/tex] and [tex]\sigma = 0.4[/tex], what value of Z (the standard normal rv) is associated with a wind speed of 15 miles per hour.

The value of Z (the standard normal rv) associated with a wind speed of 15 miles per hour.

The standard score (z) of a random variable X is calculated as follows:

[tex]z = \frac{(X - \mu)}{\sigma}[/tex]

Given: μ = 4.8, σ = 0.4

Let X be a wind speed 15 mph.

To find the standard normal rv Z associated with a wind speed of 15 miles per hour, we will use the formula for calculating the standard score (z):

[tex]z = (X - \mu) /\sigma \\z = (15 - 4.8) / 0.4\\z = 25.5[/tex]

Therefore, the value of Z (the standard normal rv) associated with a wind speed of 15 miles per hour is 25.5.

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Answer: 25

Step-by-step explanation:

Answer:

25

Step-by-step explanation:

Answer:

Step-by-step explanation:

Perimeter

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Answer:

a) To make x the subject of equation (2), we need to isolate x on one side of the equation. We can do this by adding 2 to both sides, and then dividing both sides by 6:

x - 2 = 6y

x = 6y + 2

b) We can now substitute the expression 6y + 2 for x in equation (1):

6y + 2 - 2y = 10

Simplifying the left-hand side, we get:

4y + 2 = 10

Subtracting 2 from both sides, we get:

4y = 8

Dividing both sides by 4, we get:

y = 2

Now we can substitute y = 2 back into either equation to find x. Let's use equation (2), since we have already rearranged it to make x the subject:

x = 6y + 2

x = 6(2) + 2

x = 14

Therefore, the solution to the simultaneous equations is x = 14 and y = 2.

Step-by-step explanation:

the area of the triangle KLM is 4.9 cm².

Area is the region bounded by a plane shape.

To calulate the area of the triangle, we use the formula below

Formula:

Where:

From the question,

Given:

Substitute these values into equation 1

Hence, the area is 4.9 cm².

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We can construct the 95% confidence interval for the true proportion. To do this, we need to calculate the margin of error, which is equal to the critical value (1.96) multiplied by the standard error (0.014). This equals 0.028.

The 95% confidence interval is then the sample proportion (0.38) plus or minus the margin of error (0.028). This is [tex](0.38 - 0.028, 0.38 + 0.028) = (0.352, 0.408).[/tex]

The test statistic in this case is the Z-statistic, as we are assuming that the underlying population is normally distributed. To conduct the hypothesis test, we must first state the null and alternative hypotheses.

Null Hypothesis (H0): The proportion of students at the school who fear public speaking is equal to or greater than 40%.
Alternative Hypothesis (H1): The proportion of students at the school who fear public speaking is less than 40%.

We must then calculate the test statistic, which is the Z-statistic in this case. To do this, we need to first calculate the sample proportion, which is the number of students who fear public speaking (137) divided by the total number of students surveyed (361). This equals 0.38. We then need to calculate the standard error of the sample proportion (SE), which is the square root of [tex](pq/n)[/tex], where p is the sample proportion (0.38) and q is the complement of the sample proportion (1-0.38 = 0.62). SE = [tex](0.38 x 0.62)/361 = 0.014.[/tex] The Z-statistic is then calculated as the difference between the sample proportion (0.38) and the population proportion (0.40) divided by the standard error [tex](0.014). Z = (0.38 – 0.40)/0.014 = -0.14.[/tex]

To conclude, we can use the Z-statistic and 95% confidence interval to test the hypothesis that the proportion of students at the school who fear public speaking is less than 40%. The Z-statistic of -0.14 falls within the critical region and the 95% confidence interval does not include 0.40, suggesting that the proportion of students at the school who fear public speaking is indeed less than 40%.

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If the area of the rectangle is 32 square units and its perimeter is 36 units, then the length and width of the rectangle will be given as 16 units and 2 units respectively.

Area is defined as the measure of a specific region on ground which is enclosed by a closed polygon figure. The area of a rectangle is given as the product of its length (l) and its width (b) . Perimeter on the other hand is the sum of all four sides of a rectangle and is given by the formula as follows:

Perimeter of rectangle = 2 (length + width)

Now its is given that Area= length x width

32 = l*b ... 1

36 = 2(l+b)  ... 2

Using equation 1, we get b = 32/l. Putting this value in equation 2, we get:

36 = 2 (32/l + l)

18 = 32/l + l

⇒ l^2 - 18l + 32 = 0

Solving this quadratic equation we get,

l = 16, 2

Thus the length and width of the rectangle will be equal to 16 units and 2 units respectively or vice versa.

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Refer to complete question below:

On a separate piece of paper, draw and label rectangle with an area of 32 sq. Unit and a perimeter of 36 units. Use numbers or words to show that you are correct.

Answer:

$2300

Step-by-step explanation:

$1610 is 7/10 the original cost. Multiplying by 10/7 reverses that, and we get the starting cost of $2300

Hope this helps!

The approximate area of the surface formed by revolving the polar equation over the given interval about the polar axis is 67.59 square units.

To solve the question, we can use the integration capabilities of a graphing utility to approximate to two decimal places the area of the surface formed by revolving the polar equation over the given interval about the polar axis. Polar curve is a type of curve that is made up of points that represent polar coordinates (r, θ) instead of Cartesian coordinates.

A polar curve can be represented in parametric form, but it is often more convenient to use the polar equation for a curve. According to the question, r = 7 cos(20), [0, Phi/4] is the polar equation and we need to find the approximate area of the surface formed by revolving the polar equation over the given interval about the polar axis.

To solve the problem, follow these steps: Convert the polar equation to a rectangular equation. The polar equation r = 7 cos(20) is converted to a rectangular equation using the following formulas: x = r cos θ, y = r sin θx = 7 cos (20°) cos θ, y = 7 cos (20°) sin θx = 7 cos (θ - 20°) cos 20°, y = 7 cos (θ - 20°) sin 20°

Sketch the curve in the plane. We can sketch the curve of r = 7 cos(20) by plotting the points (r, θ) and then drawing the curve through these points. Use the polar equation to set up the integral for the volume of the solid of revolution.

The volume of the solid of revolution is given by the formula: V = ∫a b πf2(x) dx where f(x) = r, a = 0, and b = Φ/4.We can find the volume of the solid of revolution using the polar equation: r = 7 cos(20) => r2 = 49 cos2(20) => x2 + y2 = 49 cos2(20)Thus, f(x) = √(49 cos2(20) - x2) = 7 cos(20°) sin(θ - 20°)

So, V = ∫a b πf2(x) dx = ∫0 Φ/4 π(7 cos(20°) sin(θ - 20°))2 dθStep 4: Use a graphing utility to evaluate the integral to two decimal places. Using a graphing utility to evaluate the integral, we get V ≈ 67.59.

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The answers are 24.50, 8.50, 23.50 respectively.

Given that we are to forecast for week 3, find the error for week 4, and make a final prediction for week 7. We are to use the moving average method with k = 2.The calculation of the moving average is shown belowWeek Time Series Moving average Error 1 30 _____ _____ 2 19 _____ 5.5 3 30 24.50 -6.50 4 16 24.50 8.50 5 21 23.00 -2.00 6 25 18.50 6.50 7 Prediction -> 23.50 -2.50The forecast for week 3 is 24.50, error for week 4 is 8.50 and final prediction for week 7 is 23.50. Thus, the answers are 24.50, 8.50, 23.50 respectively.

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The standard normal distribution is a bell-shaped curve that has a mean of 0 and a standard deviation of 1.

Standard deviation is a measure of how spread out numbers are. It is a measure of the amount of variation or dispersion from the average. For a data set, it is calculated as the square root of the variance. It is calculated by taking the square root of the variance (the average of the squared differences from the mean). The standard deviation can tell you how much variation there is from the average (mean) value in a data set.

The unit normal table is a statistical tool used to calculate probabilities related to the standard normal distribution. The standard normal distribution is a bell-shaped curve that has a mean of 0 and a standard deviation of 1. This table provides the probability of a given score falling within a certain range of the mean of the normal distribution.

For example, in part (a) the question is asking for the proportion between the mean and z = 1.96. Using the unit normal table, we can find this proportion to be 0.975. This means that 97.5% of the scores fall between the mean and z = 1.96.

In part (b), the question is asking for the proportion between the mean and z = 0. Since z = 0 is the mean, this proportion is 0.500, meaning that 50% of the scores fall between the mean and z = 0.

In part (c), the question is asking for the proportion between z = −1.90 and z = 1.90. This proportion can be found in the unit normal table to be 0.954. This means that 95.4% of the scores fall between z = −1.90 and z = 1.90.

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Complete questions as follows-
Using the unit normal table, find the proportion under the standard normal curve that lies between the following values. (Round your answers to four decimal places.)

(a) the mean and

z = 1.96


1

(b) the mean and

z = 0


2

(c)

z = −1.90 and z = 1.90


3

(d)

z = −0.40 and z = −0.30


4

(e)

z = 1.00 and z = 2.00


5

The probability that at least 2 people believe that they have seen a ufo is 0.1937102445. The probability that exactly 1 person believes that he or she has seen a ufo is problem: P(X = 1) = 10C₁ (0.10) (0.90)⁹= 0.3874204890.

The probability that at least 2 people believe that they have seen a UFO would be 0.1937102445. For this we use the binomial distribution formula.

P(X ≥ 2) = 1 − P(X = 0) − P(X = 1)P(X = 0) = (9/10)¹⁰

P(X = 1) = 10C₁ (0.10) (0.90)⁹= 0.3874204890 (rounded to 10 decimal places)

P(X ≥ 2) = 1 − 0.3874204890 − 0.3486784401 = 0.1937102445 (rounded to 10 decimal places)

The probability that 2 or 3 people believe that they have seen a UFO would be 0.1937102445. Using the formula of binomial distribution again we can solve for the probability of this event.

P(2 ≤ X ≤ 3) = P(X = 2) + P(X = 3)P(X = 2) = 10C₂ (0.10)² (0.90)⁸= 0.1937102445 (rounded to 10 decimal places)

P(X = 3) = 10C₃ (0.10)³ (0.90)⁷= 0.0573956280 (rounded to 10 decimal places)

P(2 ≤ X ≤ 3) = 0.1937102445 + 0.0573956280 = 0.2511058725 (rounded to 10 decimal places)

The probability that exactly 1 person believes that he or she has seen a UFO would be 0.3874204890. Using the binomial distribution formula to solve this problem:

P(X = 1) = 10C₁ (0.10) (0.90)⁹= 0.3874204890 (rounded to 10 decimal places)

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Answer:

We know that A receives R500 less than C, so we can write:

4x = 9x - 500

Solving for x, we get:

5x = 500

x = 100

Now we can calculate the amounts received by each person:

A = 4x = 4(100) = R400

B = 7x = 7(100) = R700

C = 9x = 9(100) = R900

To check our answer, we can verify that the ratios of the amounts received by A, B, and C are indeed 4:7:9:

A:B = 400:700 = 4:7

B:C = 700:900 = 7:9

Therefore, the total amount divided is:

400 + 700 + 900 = R2000

So the amount that is divided is R2000.

Step-by-step explanation:

The total amount of money divided is R2000.

Ratio is described as the comparison of two quantities to determine how many times one obtains the other. The proportion can be expressed as a fraction or as a sign: between two integers.

We are given that;

The ratio of A, B and C= 4:7:9

Now,

Let's start by assigning variables to the unknowns in the problem. Let's call the total amount of money "T". Then, if A receives 4x, B receives 7x, and C receives 9x, where "x" is some constant, we can write:

4x + 500 = C's share

We can also write an equation to represent the fact that the three shares add up to the total amount:

4x + 7x + 9x = T

Simplifying this equation, we get:

20x = T

Now we can substitute the first equation into the second equation and solve for x:

4x + 7x + (4x + 500) = 20x

15x + 500 = 20x

500 = 5x

x = 100

Now we can find the individual shares by multiplying x by the appropriate ratio factor:

A's share = 4x = 400

B's share = 7x = 700

C's share = 9x = 900

Finally, we can check that these add up to the total amount:

400 + 700 + 900 = 2000

Therefore, by the given ratio the answer will be R2000.

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