Answer:
[tex]-\dfrac{2}{17} + \dfrac{9}{17}i[/tex]
Step-by-step explanation:
[tex] (2 + i) \div (1 - 4i) = [/tex]
[tex] = \dfrac{2 + i}{1 - 4i} [/tex]
[tex] = \dfrac{2 + i}{1 - 4i} \times \dfrac{1 + 4i}{1 + 4i} [/tex]
[tex] = \dfrac{(2 + i)(1 + 4i)}{(1 - 4i)(1 + 4i)} [/tex]
[tex] = \dfrac{2 + 8i + i + 4i^2}{1 + 16} [/tex]
[tex] = \dfrac{2 + 9i - 4}{17} [/tex]
[tex] = \dfrac{-2 + 9i}{17} [/tex]
[tex]= -\dfrac{2}{17} + \dfrac{9}{17}i[/tex]
Meghan sells advertisements for a radio station. Each 30 second ad costs $20 per play, and each 60 second ad
costs $35 per play. Meghan sold 12 ads for $315. She wrote the system below letting x represent the number of 30
second ads and y represent the number of 60 second ads.
X+ y = 12
20x+35y = 315
What is the solution to the system of equations?
Need answers ASAP!!!!
Answer:
usai964s46s694s4o6s64694s946649s469 opps
Answer:
[tex](x,y)=(7,5)[/tex]
Step-by-step explanation:
Megan's equation will be:
[tex]20x+35y=315[/tex]
[tex]x+y=12[/tex]
Substitute [tex]x=12-y[/tex] in the first equation:
[tex]20(12-y)+35y=315[/tex]
[tex]15y=75[/tex]
[tex]y=75/15[/tex]
[tex]y=5[/tex]
Find x:
[tex]x=12-5[/tex]
[tex]x=7[/tex]
Where x and y represent 30-second and 60-second ads sold, we find that Meghan's sales were:
[tex](x,y)=(7,5)[/tex]
hope this helps....
The following is a scatterplot of the percent of children under age 18 who are not in school or in the labor force vs. the number of juvenile violent crime arrests for each of the 50 states. The least-squares regression line has been drawn in on the plot. We would like to predict what the number of juvenile violent crime arrests would be in a state if 25% of children are not in school or in the labor force. This is called
Answer:
Extrapolation
Step-by-step explanation:
From the linear regression plot created in the picture given, se could see that Tha percentage of student covered by the the plot is just above 16%. Therefore, to predict the percentage of the number of juvenile violent crime arrests would be in a state if 25% of children are not in school or in the labor force will require us to assume that the current trend continues into the future. Hence, we use the information and indications we have at present to make prediction into the future based on the assumption that we the current trend will remain relevant and applicable. This assumption into the future based on current trend is called EXTRAPOLATION.
Your sample is normally distributed with a mean age of 36. The standard deviation in this sample is 4 years. You would expect:
Kindly find complete question attached below
Answer:
Kindly check explanation
Step-by-step explanation:
Given a normal distribution with ;
Mean = 36
Standard deviation = 4
According to the empirical rule :
68% of the distribution is within 1 standard deviation of the mean ;
That is ; mean ± 1(standard deviation)
68% of subjects :
36 ± 1(4) :
36 - 4 or 36 + 4
Between 32 and 40
2.)
95% of the distribution is within 2 standard deviations of the mean ;
That is ; mean ± 2(standard deviation)
95% of subjects :
36 ± 2(4) :
36 - 8 or 36 + 8
Between 28 and 44
3.)
99% is about 3 standard deviations of the mean :
That is ; mean ± 3(standard deviation)
99% of subjects :
36 ± 3(4) :
36 - 12 or 36 + 12
Between 24 and 48
The distribution of the number of children for families in the United States has mean 0.9 and standard deviation 1.1. Suppose a television network selects a random sample of 1000 families in the United States for a survey on TV viewing habits.
Required:
a. Describe (as shape, center and spread) the sampling distribution of the possible values of the average number of children per family.
b. What average numbers of children are reasonably likely in the sample?
c. What is the probability that the average number of children per family in the sample will be 0.8 or less?
d. What is the probability that the average number of children per family in the sample will be between 0.8 and 1.0?
Answer:
a) By the Central Limit Theorem, it has an approximately normal shape, with mean(center) 0.9 and standard deviation(spread) 0.035.
b) Average numbers of children between 0.83 and 0.97 are reasonably likely in the sample.
c) 0.0021 = 0.21% probability that the average number of children per family in the sample will be 0.8 or less
d) 0.9958 = 99.58% probability that the average number of children per family in the sample will be between 0.8 and 1.0
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Mean 0.9 and standard deviation 1.1.
This means that [tex]\mu = 0.9, \sigma = 1.1[/tex]
Suppose a television network selects a random sample of 1000 families in the United States for a survey on TV viewing habits.
This means that [tex]n = 1000, s = \frac{1.1}{\sqrt{1000}} = 0.035[/tex]
a. Describe (as shape, center and spread) the sampling distribution of the possible values of the average number of children per family.
By the Central Limit Theorem, it has an approximately normal shape, with mean(center) 0.9 and standard deviation(spread) 0.035.
b. What average numbers of children are reasonably likely in the sample?
By the Empirical Rule, 95% of the sample is within 2 standard deviations of the mean, so:
0.9 - 2*0.035 = 0.83
0.9 + 2*0.035 = 0.97
Average numbers of children between 0.83 and 0.97 are reasonably likely in the sample.
c. What is the probability that the average number of children per family in the sample will be 0.8 or less?
This is the p-value of Z when X = 0.8. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.8 - 0.9}{0.035}[/tex]
[tex]Z = -2.86[/tex]
[tex]Z = -2.86[/tex] has a p-value of 0.0021
0.0021 = 0.21% probability that the average number of children per family in the sample will be 0.8 or less.
d. What is the probability that the average number of children per family in the sample will be between 0.8 and 1.0?
p-value of Z when X = 1 subtracted by the p-value of Z when X = 0.8.
X = 1
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{1 - 0.9}{0.035}[/tex]
[tex]Z = 2.86[/tex]
[tex]Z = 2.86[/tex] has a p-value of 0.9979
X = 0.8
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.8 - 0.9}{0.035}[/tex]
[tex]Z = -2.86[/tex]
[tex]Z = -2.86[/tex] has a p-value of 0.0021
0.9979 - 0.0021 = 0.9958
0.9958 = 99.58% probability that the average number of children per family in the sample will be between 0.8 and 1.0
The endpoints of PC are P(4, 1) and Q(4,8). Find the midpoint of PQ
A. (4, 4.5)
B. (0, -3.5)
C. (4.5, 4)
D. (6, 3.5)
Answer:
A. (4,4.5)
Step-by-step explanation:
Midpoint={x1+x2/2,y1+y2/2}
M={4+4/2,1+8/2}
M={8/2,9/2}
M={4,4.5}
The probability that an individual has 20-20 vision is 0.18. In a class of 12 students, what is the probability of finding five people with 20-20 vision?
0.417 or 0.185 or 0.18 or 0.037
Answer:
0.417
Step-by-step explanation:
Just divide 12/5 and the answer is 0.416666666...
Round up and you get 0.417.
Hope this helped!
Help! please don't just steal my pointss
Answer:
hi, option C is correct because it has a right angel. please give brainliest
one strip is cut into 9 equal bars shade 1/3:of strip
hiiksbsjxbxjsoahwjsissnsks
Which solution finds the value of x in the triangle below?
A right triangle is shown. The hypotenuse has a length of 8. Another side has a length of x. The angle between the hypotenuse and the other side is 60 degrees.
Answer:
4
Step-by-step explanation:
Since this is a right triangle, and one of the angles measures 60 degrees, we can conclude that the last side measures 30 degrees.
We can see that this is a 30-60-90 degree triangle.
The rules of 30-60-90 degree triangles are that the side opposite the 90 degree angle, or the hypotenuse can be measured with the variable [tex]2a[/tex]. The side opposite the 30 degree angle can be measured with [tex]a[/tex], and the side opposite the 60 degree angle will be measured with [tex]a\sqrt{3}[/tex].
We can see that 8 represents [tex]2a[/tex] because it is the hypotenuse. Since the side marked [tex]x[/tex] is separated by the hypotenuse by an angle of 60 degrees, we note that side marked [tex]x[/tex] is opposite the angle measuring 30 degrees. We note that the side opposite 30 degrees is marked [tex]a[/tex], and since we already know that 8 is equal to [tex]2a[/tex], we realize that the side marked x is equal to [tex]a[/tex], or 4.
The value of x in the triangle is 4.
What is the Pythagorean theorem ?
The square of the length of the hypotenuse of a right triangle equals the sum of the squares of the lengths of the other two sides.
It is given this is a right triangle, and one of the angles measures 60 degrees, we can conclude that the last side measures 30 degrees. By the sum of all the three interior angles of a triangle is 180 degrees
The side opposite the 90 degree angle, or the hypotenuse can be measured with the variable '2a' . The side opposite the 30 degree angle can be measured with 'a' , and the side opposite the 60 degree angle will be measured with 'a√3'.
8 represents '2a' because it is the hypotenuse. Since the side marked x is separated by the hypotenuse by an angle of 60 degrees, we note that side marked x is opposite the angle measuring 30 degrees. We note that the side opposite 30 degrees is marked 'a', and since we already know that 8 is equal to '2a', we realize that the side marked x is equal to
'a' , or 4.
2a=8
a=4
x=a=4
so, the the value of x in the triangle is 4.
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Question 4*
4. Sam's goal is to exercise for 400 minutes each
week. This week, he reached 128% of his goal.
How many minutes did he exercise?
Answer: Get at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity a week, or a combination of moderate and vigorous activity. The guidelines suggest that you spread out this exercise during the course of a week. Greater amounts of exercise will provide even greater health benefit.
Step-by-step explanation:
If Sam reached 128% of his goal to exercise each week, he would have exercised for 512 minutes.
How many minutes did Sam exercise this week?Given the parameters:
Sam's goal is to exercise for 400 minutes each week.
This week, he reached 128% of his goal.
The number of minutes =?
To determine how many minutes Sam exercised this week, we simply calculate 128% of his goal.
Number of minutes = 128% × Sam's goal of exercise
Number of minutes = 128% × 400 minutes
Note that: 128% = 128/100
Number of minutes = 128/100 × 400 minutes
Number of minutes = 128 × 4 minutes
Number of minutes = 512 minutes
Therefore, Sam exercised for 512 minutes this week.
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The triangles are similar. If QR = 9, QP = 6, and TU = 19, find TS. Round to the nearest tenth.
A) 16
B) 12.7
C) 2.8
D) 28.5
Answer:
TS = 12.7
Step-by-step explanation:
From the question given above, the following data were obtained:
QR = 9
QP = 6
TU = 19
TS =?
Since the triangles are SIMILAR, then,
QR / TU = QP / TS
With the above equation, we can obtain the value of TS as follow:
QR = 9
QP = 6
TU = 19
TS =?
QR / TU = QP / TS
9 / 19 = 6 / TS
Cross multiply
9 × TS = 19 × 6
9 × TS = 114
Divide both side by 9
TS = 114 / 9
TS = 12.7
ABC ∆ where Angle A =90° , AB = 12 m, AC = 9 m . Find BC ?
( Show all your workings )
best answer will marked as brainalist
dont put fake ones
Answer:
15m
Step-by-step explanation:
Use Pythagoras
Folow the steps in the image
Answer:
:] brainlist me friends
The graph shows a line of best fit for data collected on the average temperature, in degrees Fahrenheit, during a month and the
number of inches of rainfall during that month.
у
90
801
70
Average Temp
20
10
Inches of Rain
The equation for the line of best fit is y=-3.32x +97.05.
Based on the line of best fit, what would be the prediction for the average temperature during a month with 13.25 inches of rainfall?
Answer:
53.06°F
Step-by-step explanation:
Given the equation of best fit :
y=-3.32x +97.05.
The average temperature for a month with 13.25 inches of Rainfall
Amount of Rainfall = x
Average temperature = y
To make our prediction ; put x = 13.25 in the equation and solve for y ;
y = -3.32x +97.05
Put x = 13.25
y = -3.32(13.25) +97.05
y = - 43.99 + 97.05
y = 53.06°F
Recall the creative calligraphy case we discussed in class. Suppose you have received a rush order of 55 invitations that have to be created in the next (four hour) work session. What is the most time You (i.e. not Susie) can spend writing on the card and envelope for each invitation and still fill the order
Answer:
About 4 minutes and 3 seconds
Step-by-step explanation:
If I have 55 invitations to be created in four hours.
4 hours × 60 =240 minutes
240/55= 4.36 minutes
So if I spend 4 minutes and 3 seconds on an invitation, I should be able to fill the order.
36x^2=y^2
Does the equation define y as a function of x ?
Answer:
ya the equation divides y as a function of x
In the diagram, point D is the center of the medium-sized circle that passes through C and E, and it is also the center of the largest circle that passes through A and G. Each of the diameters of the small circles with centers B and F equals the radius of the medium-sized circle with center D. The shaded area is what fraction of the largest circle?Single choice.
9514 1404 393
Answer:
5/8
Step-by-step explanation:
The area of the smaller circles is proportional to the square of the ratio of their diameters. The two smallest circles have diameters equal to 1/4 the diameter of the largest circle. Hence their areas are (1/4)^2 = 1/16 of that of the largest circle.
Similarly, the medium circle has a diameter half that of the largest circle, so its area is (1/2)^2 = 1/4 of the are of the largest circle.
The smaller circles subtract 2×1/16 +1/4 = 3/8 of the area of the largest circle. Then the shading is 1-3/8 = 5/8 of the area of the largest circle.
one number is seven less than the second number. five times the first is 9 more than 6 times the second. find the numbers
Step-by-step explanation:
2nd number = x
1st number = x - 7
5 (x - 7) = 6x + 9
5x - 35 = 6x + 9
- x = 44
x = - 44
1st number = -51
2nd number = -44
Proof: 5 (-51) = 6(-44) + 9
-255 = -264 + 9
-255 = -255
hope it helps.
Also, I think that Brainly is an awesome app, but there's an app which is doing great work for me in maths, named Gauthmath. I will suggest it. Video concepts and answers from real tutors.
Which of the following numbers is rational? Assume that the decimal patterns continue.
Answer:
[tex]\sqrt{49}[/tex]
Step-by-step explanation:
Define a rational number by a number able to expressed a fraction where the denominator is not 0 or 1.
Non-terminating (never-ending) decimals cannot be expressed as a fraction and therefore are irrational. However, recall that [tex]\sqrt{49}=7[/tex], which can be expressed as a fraction (e.g. [tex]\frac{14}{2}[/tex], etc). Thus, the answer is [tex]\boxed{\sqrt{49}}[/tex].
Choose which triangle goes into the right category.
Answer:
obtuse cant be a right angle
Step-by-step explanation:
in order to be obtuse you have to be more than 90 dagrees
Find the 11th term of the sequence
3, -6, 12, -24,...
3072
6144
-6144
-3072
Answer:
-3072
Step-by-step explanation:
What is the product (4.42 x 103)(5 x 10^) written in
scientific notation?
Answer:
2.2763 x 10 to the power of 4
for some reason it doesn't let me put in the explanation
The system of equations y = negative one-fifth x minus 6 and y = –2x + 3 is shown on the graph below.
On a coordinate plane, 2 lines intersect at (5, negative 7).
According to the graph, what is the solution to this system of equations?
(5, –7)
(–7, 5)
(5, 7)
(7, 5)
Answer:
According to graph, solution is (5, –7)
Answer:
A) (5, –7)
Step-by-step explanation:
I got 100%, please brainlist
Can someone give me the letter to all answers 1-4 or at least one 3
Answer:
hello there here are your answers:
1) a- 12, 18, 24, 30, 36
2) b- 31
3) a-communitive property of addition
4) a- 6a
Step-by-step explanation:
1: go through all the numbers and add 6 like 12+6=16 etc.
2: the common difference is 4 so 27+4 =31
3: communitive property because you can change the number in any order and still get the same sum
4: 6a because only 24ab has a b in it
A researcher believes that 9% of males smoke cigarettes. If the researcher is correct, what is the probability that the proportion of smokers in a sample of 664 males would differ from the population proportion by greater than 3%
Answer:
0.0070 = 0.70% probability that the proportion of smokers in a sample of 664 males would differ from the population proportion by greater than 3%
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
A researcher believes that 9% of males smoke cigarettes.
This means that [tex]p = 0.09[/tex]
Sample of 664
This means that [tex]n = 664[/tex]
Mean and standard deviation:
[tex]\mu = p = 0.09[/tex]
[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.09*0.91}{664}} = 0.011[/tex]
What is the probability that the proportion of smokers in a sample of 664 males would differ from the population proportion by greater than 3%?
Proportion below 9 - 3 = 6% or above 9 + 3 = 12%. Since the normal distribution is symmetric, these probabilities are equal, so we find one of them and multiply by 2.
Probability the proportion is below 6%
P-value of Z when X = 0.06. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.06 - 0.09}{0.011}[/tex]
[tex]Z = -2.7[/tex]
[tex]Z = -2.7[/tex] has a p-value of 0.0035
2*0.0035 = 0.0070
0.0070 = 0.70% probability that the proportion of smokers in a sample of 664 males would differ from the population proportion by greater than 3%
Can anyone help please?
Answer:
h(t) = -16t(t-6)
h(2) = 128
Step-by-step explanation:
h(t) = -16t² + 96t
h(t) = -16t(t-6)
t = 3
h(2) = -16(2)(2 - 6)
h(2) = 128
A school band found they could arrange themselves in rows of 6, 7, or 8 with no one left over. What is the minimum number of students in the band?
Answer:
168 is the answer if i m not wrong.I took the LCM.
If school band found they could arrange themselves in rows of 6, 7, or 8 with no one left over, the minimum number of students in the band is 168.
To find the minimum number of students in the band, we need to determine the least common multiple (LCM) of the numbers 6, 7, and 8.
The LCM is the smallest multiple that is divisible by all the given numbers.
Prime factorizing each number, we have:
6 = 2 * 3
7 = 7
8 = 2 * 2 * 2
To find the LCM, we take the highest exponent for each prime factor:
2³ * 3 * 7 = 168
By having 168 students, they can arrange themselves into rows of 6 (28 rows), 7 (24 rows), or 8 (21 rows) without anyone being left over. Any fewer than 168 students would result in at least one row having students left over.
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Enter an equation in point-slope form for the line.
Slope is −6 and (1, 1) is on the line.
Answer:
y - 1 = -6(x - 1)
General Formulas and Concepts:
Algebra I
Point-Slope Form: y - y₁ = m(x - x₁)
x₁ - x coordinate y₁ - y coordinate m - slopeStep-by-step explanation:
Step 1: Define
Identify
Point (1, 1)
Slope m = -6
Step 2: Find Equation
Substitute in variables [Point-Slope Form]: y - 1 = -6(x - 1)find the slope of a line perpendicular to the line below. y=2x+4
Tim and Al are bricklayers. Tim can construct an outdoor grill in 5 days. If Al helps Tim, they can build it in only 3 days. How long
would it take Al to build the grill alone? Write your answer as an integer, simplified fraction, or mixed number.
It would take Al
days to build the grill alone.
Answer:
It would take Al 7.5 days to build the grill alone.
Step-by-step explanation:
Since Tim and Al are bricklayers, and Tim can construct an outdoor grill in 5 days, and if Al helps Tim, they can build it in only 3 days, to determine how long would it take Al to build the grill alone should be done the following calculation:
1/5 + X = 1/3
0.20 + X = 0.333
X = 0.333 - 0.20
X = 0.1333333
X = 1 / 7.5
Therefore it would take Al 7.5 days to build the grill alone.
A rectangle's length is three times as long as it is wide. Which expression represents the change in area if the width of the rectangle is increased by 1?
1. 3x^2
2. 3x
3. 3x^2+3x
4. the area increases by 3
Step-by-step explanation:
Let's say the rectangle's width is equal to y. We know that the length is three times the width, so the length = 3 * y. We also know that the area for a rectangle is equal to length * width, so the area, z, is equal to
(3*y) * y = z
3 * y² = z
Now, let's increase the width of the rectangle by 1. We can replace y with y+1 (as y+1 is 1 greater than y), and 3 * y with 3 * (y+1) to get
3*(y+1) * (y+1) = new area
(3y+3)*(y+1) = new area
3y²+3y +3 y + 3 = new area
3y² + 6y + 3 = new area
The difference in area is equal to the new area subtracted by the old area, or
3y²+6y+3 - 3y² = 6y +3. The variable for x is not given, so if x = (2y+1), the answer would be the second choice. However, solely using the information given, it is impossible to determine a solution outside of saying that it is not option 4, as 6y + 3 ≠ 3