Amanda made $154 for 11 hours of work. At the same rate, how many hours would she have to work to make $252?

What do you want to find out? > The rate at which Bill puts shringles on a rood. What do you know? > Bill and Chip each fi

denis23 [38]

Answer:

(a) b = (4/7)c

(b) Bill: 40 shingles/hour; Chip: 70 shingles/hour

Step-by-step explanation:

Let b and c represent Bill's and Chip's rates in shingles per hour, respectively. Then we have ...

7b = 4c

c - b = 30 . . . . shingles per hour difference in rates

(a) Bill's rate in terms of Chip's rate can be found by dividing the first equation by 7

b = (4/7)c . . . . . Bill's rate is 4/7 of Chip's rate

__

(b) To find the rates, we can multiply the second equation by 7 and substitute using the first equation:

7c -7b = 210

7c -4c = 210

c = 210/3 = 70

b = (4/7)(70) = 40

Bill's rate is 40 shingles per hour; Chip's rate is 70 shingles per hour.

3 0

3 years ago

Determine if the following lengths make an acute, right or obtuse

Rzqust [24]

Answer:

acute

Step-by-step explanation:

cause

4 0

3 years ago

If you have a room with four walls and a ceiling, how would you label the walls (plane, line, or point)? How would you label

Sergio039 [100]

Walls = Plane

Intersection = line

Corner = Point

3 0

3 years ago

According to the WHO MONICA Project the mean blood pressure for people in China is 128 mmHg with a standard deviation of 23 mmHg

Sati [7]

Answer:

a) Mean blood pressure for people in China.

b) 38.21% probability that a person in China has blood pressure of 135 mmHg or more.

c) 71.30% probability that a person in China has blood pressure of 141 mmHg or less.

d) 8.51% probability that a person in China has blood pressure between 120 and 125 mmHg.

e) Since Z when X = 135 is less than two standard deviations from the mean, it is not unusual for a person in China to have a blood pressure of 135 mmHg

f) 157.44mmHg

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

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 pvalue, we get the probability that the value of the measure is greater than X.

If X is two standard deviations from the mean or more, it is considered unusual.

In this question:

$\mu = 128, \sigma = 23$

a.) State the random variable.

Mean blood pressure for people in China.

b.) Find the probability that a person in China has blood pressure of 135 mmHg or more.

This is 1 subtracted by the pvalue of Z when X = 135.

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{135 - 128}{23}$

$Z = 0.3$

$Z = 0.3$ has a pvalue of 0.6179

1 - 0.6179 = 0.3821

38.21% probability that a person in China has blood pressure of 135 mmHg or more.

c.) Find the probability that a person in China has blood pressure of 141 mmHg or less.

This is the pvalue of Z when X = 141.

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{141 - 128}{23}$

$Z = 0.565$

$Z = 0.565$ has a pvalue of 0.7140

71.30% probability that a person in China has blood pressure of 141 mmHg or less.

d.)Find the probability that a person in China has blood pressure between 120 and 125 mmHg.

This is the pvalue of Z when X = 125 subtracted by the pvalue of Z when X = 120. So

X = 125

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{125 - 128}{23}$

$Z = -0.13$

$Z = -0.13$ has a pvalue of 0.4483

X = 120

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{120 - 128}{23}$

$Z = -0.35$

$Z = -0.35$ has a pvalue of 0.3632

0.4483 - 0.3632 = 0.0851

8.51% probability that a person in China has blood pressure between 120 and 125 mmHg.

e.) Is it unusual for a person in China to have a blood pressure of 135 mmHg? Why or why not?

From b), when X = 135, Z = 0.3

Since Z when X = 135 is less than two standard deviations from the mean, it is not unusual for a person in China to have a blood pressure of 135 mmHg.

f.) What blood pressure do 90% of all people in China have less than?

This is the 90th percentile, which is X when Z has a pvalue of 0.28. So X when Z = 1.28. Then

X = 120

$Z = \frac{X - \mu}{\sigma}$

$1.28 = \frac{X - 128}{23}$

$X - 128 = 1.28*23$

$X = 157.44$

So

157.44mmHg

6 0

3 years ago

PLEASE HELP!!! Due very soon!! - The graph below represents the height of a football pass, in feet, x seconds after it is thrown

ELEN [110]

Answer:

The answer is D.

Step-by-step explanation:

By the time 4 seconds has passed, the line is at the bottom of the graph, which represents the time the ball has landed. I hope this helps.

3 0

3 years ago