Find the area of the following composite figure

Jackie and Rachel both worked during last summer and made $960 each. Rachel worked 16 hours more than Jackie, but Rachel earned

Pavel [41]

Answer:

The number of hours Jackie worked = 80hours

Step-by-step explanation:

Last summer:

Jackie made $960

Rachel made $960

let number of hours Jackie worked = x

Rachel worked 16 hours more than Jackie:

Number of hours Rachel worked = x + 16

if Jackie earned $y per hour

Rachel earned $2 less per hour = y-2

Jackie: 960 = x × y = xy

Rachel: 960 = (x+16)(y-2)

960 = xy -2x +16y -32

recall xy = 960, insert the value for xy

960 = 960 - 2x +16y -32

- 2x +16y -32 = 0

2x -16y = -32

x-8y = -16

x = 8y-16

recall xy = 960, insert the expression for x

(8y-16)y = 960

8y² -16y = 960

y² -2y - 120 = 0

y²+10y-12y -120 = 0

y(y+10) -12(y+10) = 0

(y-12) = 0 or (y+10) = 0

y = 12 or -10

since y can't be negative, y = 12

x = 8y-16

x = 8(12) -16 = 80

The number of hours Jackie worked = x = 80 hours

7 0

3 years ago

The sum of a certain number and -3.4 is -8.1 find the number

kirza4 [7]

Answer:

-4.7

Explanation:

-4.7 + -3.4 = -8.1

I’m giving you an Integer Rule Cheat Sheet that I use. Hopefully it can help you with Math problems like this!

6 0

3 years ago

Read 2 more answers

One estimate shows that the number of people without access to safe drinking water is about one billion. How much water is requi

gizmo_the_mogwai [7]

Answer:

Step-by-step explanation:

1 billion = 10^9

10^9 people * (10 Liters)/person = 10^10 Liters

3 0

3 years ago

If the area of a square living room is 169 square feet . What is the perimeter of the room

stich3 [128]

The one wall would be 13 feet long.
13+13+13+13= 52 feet.

8 0

3 years ago

Read 2 more answers

Boxes of raisins are labeled as containing 22 ounces. Following are the weights, in the ounces, of a sample of 12 boxes. It is r

ZanzabumX [31]

Answer:

A 90% confidence interval for the mean weight is [21.78 ounces, 21.98 ounces].

Step-by-step explanation:

We are given the weights, in the ounces, of a sample of 12 boxes below;

Weights (X): 21.88, 21.76, 22.14, 21.63, 21.81, 22.12, 21.97, 21.57, 21.75, 21.96, 22.20, 21.80.

Firstly, the pivotal quantity for finding the confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean weight = $\frac{\sum X}{n}$ = 21.88 ounces

s = sample standard deviation = $\sqrt{\frac{\sum (X-\bar X)^{2} }{n-1} }$ = 0.201 ounces

n = sample of boxes = 12

$\mu$ = population mean weight

Here for constructing a 90% confidence interval we have used a One-sample t-test statistics because we don't know about population standard deviation.

So, 90% confidence interval for the population mean, $\mu$ is ;

P(-1.796 < $t_1_1$ < 1.796) = 0.90 {As the critical value of t at 11 degrees of

freedom are -1.796 & 1.796 with P = 5%}

P(-1.796 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 1.796) = 0.90

P( $-1.796 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.796 \times {\frac{s}{\sqrt{n} } }$ ) = 0.90

P( $\bar X-1.796 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.796 \times {\frac{s}{\sqrt{n} } }$ ) = 0.90

90% confidence interval for $\mu$ = [ $\bar X-1.796 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+1.796 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $21.88-1.796 \times {\frac{0.201}{\sqrt{12} } }$ , $21.88+1.796 \times {\frac{0.201}{\sqrt{12} } }$ ]

= [21.78, 21.98]

Therefore, a 90% confidence interval for the mean weight is [21.78 ounces, 21.98 ounces].

8 0

3 years ago

Find the area of the following composite figure​

Find the area of the following composite figure