The half-life of a radioactive substance is the time it takes for a quantity of the substance to decay to half of the initial amount. The half-life of the radioactive gas radon is approximately 2.8 days. The initial amount of radon used in an experiment is 74 grams. If N represents the number of grams of radon remaining t days after the start of the experiment,

1/2 bxh

1/2 30 x 12

15 x12

=12

Answer:

y = - (x - 3)² + 15

Step-by-step explanation:

using the method of completing the square

y = x² + 6x + 6 ← factor out - 1 from the first 2 terms

y = - (x² - 6x) + 6

to complete the square

add/subtract ( half the coefficient of the x- term )² to x² - 6x

y = - (x² + 2(- 3)x + 9 - 9) + 6

  = - (x - 3)² + 9 + 6

  = - (x - 3)² + 15

Answer:

106

Step-by-step explanation:

a foot is 12 inches so 8x12 would be 96 and if you add the other 10 inches that would be 106

Answer: (1)

Step-by-step explanation:

A system of equations must have two equations. The first option is the only one that satisfies this.

Answer:

[tex]\sqrt{2}[/tex] A.

Step-by-step explanation:

There's a few ways you can go about solving this, but the way I would go with is using sine law.

Sine law:

[tex]\frac{sinA}{a} = \frac{sinB}{b}[/tex]

in the equation above 'A' an angle, and 'a' would be the length of the side opposite to it. Same thing for B.

You are given the angle 90 degrees, and its opposite side length is 2.

You are also given 45 degrees from one of the corners but it doesn't tell you its side length.

There is one corner where it doesn't tell you the angle but you can figure it out using the law that the angles in a triangle must add up to 180 degrees.

So you subtract the other angles to find the angle of the bottom right angle.

180-90-45 = 45

The reason we want to find that angle, is so we can use sin law to find s.

Write down what you have so far:

[tex]\frac{sin90}{2} = \frac{sin45}{s}[/tex]

Now all you need to do is solve for s.

[tex]\frac{sin90*s}{2} = \frac{sin45}{1}[/tex]

sin 90 is 1.

[tex]\frac{1*s}{2} = sin45\\ \\s = 2*sin45\\\\[/tex]

Now since the answers available are in exact values, you can't just punch this in your calculator.

[tex]sin45 = \frac{\sqrt{2} }{2}\\ \\[/tex]

so,

[tex]s = 2*\frac{\sqrt{2} }{2} = \sqrt{2}[/tex]

Sale price of the crate of pears after 10% discount on cost price $50 is equals to $45.

" Sale price is defined as the amount on which something is sold out."

Formula used

Sale price = Cost price - Discount amount

According to the question,

Cost price of the crate of pears = $50

Discount  on sale price = 10%

Discount amount = 10% of $50

                             [tex]=\frac{10}{100}(50) \\\\= \$5[/tex]

Substitute the value in the formula of sale price we get,

Sale price = [tex]\$ ( 50 - 5)[/tex]

                 = $ 45

Hence, sale price of the crate of pears after 10% discount on cost price $50 is equals to $45.

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Answer:

- 4 < x < 2

Step-by-step explanation:

- 1 < x + 3 < 5  ( subtract 3 from each of the 3 intervals )

- 4 < x < 2

-1 < x + 3 < 5

Then subtract 3 from each of the 3 intervals

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[tex]135 = \frac{22 + 8}{2} \times h \\ 135 = \frac{30}{2} \times h \\ 135 = 15 \times h \\ h = \frac{135}{15} \\ h = \frac{27}{3} = 9cm[/tex]

Answer:

Area of a trapezoid :

[tex]area = \frac{a + b}{2} h[/tex]

The measures given are trapezoid

Area = 135

base 1 = 22

base 2 = 8

[tex]135 = \frac{22 + 8}{2} h \\ \\135 = \frac{30}{2} h \\ 2(135) = ( 2)\frac{30}{2} h \\ 270 = 30h \\ \frac{270}{30 } = \frac{30h}{30} \\ 9 = h[/tex]

Step-by-step explanation:

We can check if the answer is right

[tex] \frac{22 + 8}{2} \times 9 \\ \frac{30}{2} \times 9 \\ 15 \times 9 = 135[/tex]

Answer:

4:18

6:27

8:36

Hope this helps! :)

The average is the arithmetic mean of all the observations of a set of numbers. The number of times Brandon rolls above the average is 7.

The average is the arithmetic mean of all the observations of a set of numbers. it is found by dividing the sum of all the observations of the set by the number of observations in the set.

[tex]\rm{Average=\dfrac{Sum\ of\ observations}{Number\ of\ observations}[/tex]

In order to know the number of times Brandon rolls the dice above the average, we first need to calculate the average of the twenty rolls.

The average of the 20 times dice rolls,

[tex]\rm Average = \dfrac{6+1+3+4+4+4+6+5+5+3+6+4+4+5+2+3+5+4+4+2}{20}[/tex]

[tex]\rm Average = \dfrac{80}{20} = 4[/tex]

Thus, the average of the 20 rolls of the dice is 4.

Now, the number of times the result of the dice roll is above 4(x>4) is 7.

Hence, the number of times Brandon rolls above the average is 7.

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Each shows two lines that make up a system of equations. If the graphs of the equations intersect, then there is one solution that is true for both equations. If the graphs of the equations do not intersect (for example, if they are parallel), then there are no solutions that are true for both equations.

Answer:

4 pepperoni pizzas

Step-by-step explanation:

3 cheese => 1 pepperoni

12cheese (3x4) => 4 (1x4) pepperoni

- 5 + 5x = - 1 + 6x

- 5 + 5 + 5x = - 1 + 5 + 6x

5x = 4 + 6x

5x - 6x = 6x - 6x + 4

- x = 4

x = - 4

Answer:

The answer is that x = -4.

Step-by-step explanation:

You first take away the parenthesis so it would look like this: -5+5x=-1+6x

Then, you add 5 to both sides of the problem: -5+5x+5=-1+6x+5

Then, you simplify it down: 5x=6x+4

You then subtract 6x from each side: 5x-6x=6x+4-6x

Then simplify again: -x=4

Then, divide both sides by -1: -x/-1 = 4/-1

Then simplify to get x = -4.

Answer: w=8.5

Step-by-step explanation:

Just did it.

Answer:

0.7778

Step-by-step explanation:

step 1

Address the input parameters and observe what to be found:

Input values:

The fraction = 21/27

What to be found:

Find the decimal expansion of fraction 21/27.

step 2

The numerator is smaller than the denominator of the fraction 21/27, so find how many 10s should be multiplied with both numerator and denominator. Since the number of digits are equal in both numerator and denominator, multiply 10 with both numerator and denominator of 21/27.

=21

27

x10

10

step 3

Rearrange the fraction as like the below:

=10 x 21

27

x1

10

=210

27

x1

10

step 4

Simplify the above expression further:

=210

27

x1

10

=189 + 21

27

x1

10

= (189

27

+21

27

) x1

10

= (7 + 21

27

) x 1

10

step 5

Repeat the step 2 to find the decimal equivalent for the fraction 21/27 in the above expression:

= (7 + 21

27

) x 1

10

= (7 + 0.778) x1

10

step 6

Simplify the above expression further:

= (7 + 0.778) x1

10

= 7.778 x1

10

=7.778

10

21

27

= 0.7778

Hence,

21/27 as a decimal is 0.7778

Step-by-step explanation:

so,

1cm : 4m

that means the factor is 1/400 (as 1 m = 100 cm).

also to remember : 1 m² = 100cm×100cm = 10,000 cm²

the area of a rectangle is

length × width

if both dimensions are shortened by a factor (1/400) in our case :

length×1/400 × width×1/400 =

= length × width × 1/400² = length × width × 1/160,000

that means the area of the actual tennis court is

160,000 times the area of the blueprint picture :

160,000 × 16.25 = 2,600,000 cm² = 260 m²

we now know that the actual length of the tennis court is 400 times the length of the blueprint length :

400 × 6.25 = 2,500 cm = 25 m

Answer:

1.b

2.c

3.a

4.a

5.d

Step-by-step explanation:

Answer:

Step-by-step explanation:

So this is a cylinder

R= 8.75in

h=43.12in

So it will be = 3.14x8.75²x43.12

=> 3.14x76.5625x43.12

3.14x 3301.375

i think it is correct

.

stay safe

.

have a nice TIME

Answer:

3(9e + 8)

Step-by-step explanation:

the highest common factor is 3 so factor it out.

Answer:

[tex]\displaystyle 3[9e + 8][/tex]

Explanation:

Sinse you were not specific in your approach, it is safe to assume that you were probably looking for how to factour this expression, and the way to do to this is to factour a 3 out the expression sinse both quantities have a common divisour of 3:

24: 1, 2, 3, 4, 6, 8, 12, 24

27: 1, 3, 9, 27

I am joyous to assist you at any time.

Answer:

7⁵-3=7⁵x- 19

Step-by-step explanation:

16807 - 3 = 7⁵x - 19

16804 = 7⁵x - 19

16804 = 16807x - 1

adding 19 on both sides

16804 + 19 = 16807x - 19 + 19

16823 = 16807x

x = 16823 / 16807

16823 upon 16807 is the x

Answer:

Step-by-step explanation:

Answer:

See below ↓

Step-by-step explanation:

Solve for x.

2.1.1

2.1.2

2.1.3

I can only answer 3 questions together at maximum so kindly post the rest of your questions 3 at a time separately.

Hope this helped~

Answer:

x = a/(p+q)

x = 2 or x = 1/2

x = -2

m≤ -1 or m<4

-1 , 0 , 1 , 2 and 3.....................since : -1 ≥ m < 4.

x = -3 and y = 9.

Step-by-step explanation:

The first one is just making x to be the subject of the formula by factorising p and q. Then dividing both sides by (p + q).

px + qx = a........................... x (p + q) = a............divide sides by ( p+q) to get the expression.

Solve quadratically for the second one.

For the third one, apply the laws of indices to work out.

32 = ( 1/2)^-5..............so, ( 1/2)^3x + 1   = ( 1/2)^-5.......Drop the base numbers since they are common.

3x + 1 = -5.........then solve to get x as -2.

For the fourth one, we solve for m by separating it into 2.

the first one is: -11 ≤ 3m - 8.

the second one: 3m - 8 < 4

then solve like a normal equation but maintain the inequality signs.

For the integral values, you'll get them from the answers because the answers are a range

The last one you solve simultaneously either by substitution or elimination method.

HOPE THIS HELPS

Answer:

the answer is c

Step-by-step explanation:

45% of 1500=675

38% of 1500=570

675+570=1245

1500-1245=255

Answer:

Step-by-step explanation:

The y-intercept is the point where the graph cuts the y axis - that is when x = 0.

f(x)=138⋅1.9x

ehen x = 0 f(x) = 0 so the y-intercept is at (0, 0).

Answer:

Fraction form: 1/8

Decimal form: 0.125

Step-by-step explanation:

Slope of line = [-6 - (-8)]/[8 - ( -8)]

= [-6 + 8]/[8 + 8]

= 2/16

= 1/8

= 0.125