All categories

2 years ago

Find the dimension of a rectangle whose width is 10 miles less than its length and whose area is 75 square miles

Mathematics

2 answers:

cestrela7 [59]2 years ago

5 0

Answer:

The length is 15 miles and the width is 5 miles.

Step-by-step explanation:

The rectangle has two dimensions, width w and length l.

The area is given by the following formula:

$S = wl$ .

In this problem, we have that:

The width is 10 miles less than its length. This means that

$w = l - 10$

The area is 75 square miles. So

$wl = 75$

$(l - 10)l = 75$

$l^{2} - 10l - 75 = 0$ .

$l = 15$ and $l = -5$ .

We cannot have negative dimensions. This means that the length is 15 miles and the width is 5 miles.

jek_recluse [69]2 years ago

4 0

W = L - 10
75 = L × ( L - 10 )
75 = L^2 - 10L
L^2 - 10L - 75 = 0
( L - 15 ) ( L + 5 ) = 0
L = 15

w = 15 - 10
w = 5

2 dimension

You might be interested in

Power +, Inc. produces AA batteries used in remote-controlled toy cars. The mean life of these batteries follows the normal prob

Novay_Z [31]

Answer:

a) By the Central Limit Theorem, it is approximately normal.

b) The standard error of the distribution of the sample mean is 1.8333.

c) 0.1379 = 13.79% of the samples will have a mean useful life of more than 38 hours.

d) 0.7939 = 79.39% of the samples will have a mean useful life greater than 34.5 hours

e) 0.656 = 65.6% of the samples will have a mean useful life between 34.5 and 38 hours

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 $\mu$ and standard deviation $\sigma$ , the z-score 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 p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Mean of 36 hours and a standard deviation of 5.5 hours.

This means that $\mu = 36, \sigma = 5.5$

a. What can you say about the shape of the distribution of the sample mean?

By the Central Limit Theorem, it is approximately normal.

b. What is the standard error of the distribution of the sample mean? (Round your answer to 4 decimal places.)

Sample of 9 means that $n = 9$ . So

$s = \frac{\sigma}{\sqrt{n}} = \frac{5.5}{\sqrt{9}} = 1.8333$

The standard error of the distribution of the sample mean is 1.8333.

c. What proportion of the samples will have a mean useful life of more than 38 hours?

This is 1 subtracted by the pvalue of Z when X = 38. So

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

By the Central Limit Theorem

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

$Z = \frac{38 - 36}{1.8333}$

$Z = 1.09$

$Z = 1.09$ has a pvalue of 0.8621

1 - 0.8621 = 0.1379

0.1379 = 13.79% of the samples will have a mean useful life of more than 38 hours.

d. What proportion of the sample will have a mean useful life greater than 34.5 hours?

This is 1 subtracted by the pvalue of Z when X = 34.5. So

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

$Z = \frac{34.5 - 36}{1.8333}$

$Z = -0.82$

$Z = -0.82$ has a pvalue of 0.2061.

1 - 0.2061 = 0.7939

0.7939 = 79.39% of the samples will have a mean useful life greater than 34.5 hours.

e. What proportion of the sample will have a mean useful life between 34.5 and 38 hours?

pvalue of Z when X = 38 subtracted by the pvalue of Z when X = 34.5. So

0.8621 - 0.2061 = 0.656

0.656 = 65.6% of the samples will have a mean useful life between 34.5 and 38 hours

4 0

3 years ago

What is the equation x^2+12x-3=16 written in the form (x-p)^2=q using the method of completing the square ?

Alexus [3.1K]

Step-by-step explanation:

${x}^{2} + 12x - 3 = 16$

${x}^{2} + 12x = 19$

${x}^{2} + 12x + 36 = 19 + 36$

$(x + 6) {}^{2} = 55$

3 0

3 years ago

Add three data values to the following data set so the mean increases by 10 but the median does not change. The numbers are 42 3

777dan777 [17]

In order the numbers are 20, 29, 32, 37, 42.
So that means the median is 32. In order for the median to stay the same one of the three data values must be 32 as well as adding a number to each side of the ends. One 32 or less another 32or more.
The mean right now is: 20+29+32+37+42=160 and there are 5 values.
Mean: 160/5=32
For it to increase by 10 it has to be 42.
extra 3 numbers I used were 31, 32, & 113 (those are your answer)

3 0

3 years ago

Help me please !!!!!!!!!!!!!!

tensa zangetsu [6.8K]

Answer:

$\large\boxed{V=\dfrac{49\pi}{3}\ in^3}\approx51.29\ in^3}$