4/5 n = 9/10 solve n

Mrs. Chip bought 2 sheets and a blanket and paid $41. Mrs. Dale bought a sheet and 4 blankets and paid $80.

Katyanochek1 [597]

Answer:

Sheet = $12
Blanket = $17

Step-by-step explanation:

Let the cost of a sheet be s and cost of a blanket be b

2s + b = 41
s + 4b = 80

From the first equation we get:

b = 41 - 2s

Substitute in the second equation

s + 4*(41 - 2s) = 80
s + 164 - 8s = 80
7s = 84
s = 12

Then

b = 41- 2*12 = 17

6 0

3 years ago

The 2008 Workplace Productivity Survey, commissioned by LexisNexis and prepared by WorldOne Research, included the question, "Ho

vitfil [10]

Answer:

Therefore, the sampling distribution of $\bar{x}$ is normal with a mean equal to 9 hours and a standard deviation of 0.7969 hours.

The 95% interval estimate of the population mean $\mu$ is

LCL = 7.431 hours to UCL = 10.569 hours

Step-by-step explanation:

Let X be the number of hours a legal professional works on a typical workday. Imagine that X is normally distributed with a known standard deviation of 12.6.

The population standard deviation is

$\sigma = 12.6 \: hours$

A sample of 250 legal professionals was surveyed, and the sample's mean response was 9 hours.

The sample size is

$n = 250$

The sample mean is

$\bar{x} = 9 \: hours$

Since the sample size is quite large then according to the central limit theorem, the sample mean is approximately normally distributed.

The population mean would be the same as the sample mean that is

$\mu = \bar{x} = 9 \: hours$

The sample standard deviation would be

$s = {\frac{\sigma}{\sqrt{n} }$

Where is the population standard deviation and n is the sample size.

$s = {\frac{12.6}{\sqrt{250} }$

$s = 0.7969 \: hours$

Therefore, the sampling distribution of $\bar{x}$ is normal with a mean equal to 9 hours and a standard deviation of 0.7969 hours.

The population mean confidence interval is given by

$\text {confidence interval} = \mu \pm MoE\\\\$

Where the margin of error is given by

$$ MoE = t_{\alpha/2}(\frac{s}{\sqrt{n} } ) $ \\\\$

Where n is the sampling size, s is the sample standard deviation and is the t-score corresponding to a 95% confidence level.

The t-score corresponding to a 95% confidence level is

Significance level = α = 1 - 0.95 = 0.05/2 = 0.025

Degree of freedom = n - 1 = 250 - 1 = 249

From the t-table at α = 0.025 and DoF = 249

t-score = 1.9695

$MoE = t_{\alpha/2}(\frac{\sigma}{\sqrt{n} } ) \\\\MoE = 1.9695\cdot \frac{12.6}{\sqrt{250} } \\\\MoE = 1.9695\cdot 0.7969\\\\MoE = 1.569\\\\$

So the required 95% confidence interval is

$\text {confidence interval} = \mu \pm MoE\\\\\text {confidence interval} = 9 \pm 1.569\\\\\text {LCI } = 9 - 1.569 = 7.431\\\\\text {UCI } = 9 + 1.569 = 10.569$

The 95% interval estimate of the population mean $\mu$ is

LCL = 7.431 hours to UCL = 10.569 hours

8 0

3 years ago

{(-3.7).(-5, -8), (-6, -1). (-9, -1), (0, -3) }

zhenek [66]

Answer:

The domain is the set of all the values of x, so it would be -3, -5, -6, -9, 0. The range would be every set of y, so it would be 7, -8, -1, -3. Finally, this relation is indeed a function.

Domain: -3, -5, -6, -9, 0

Range: 7, -8, -1, -3

Is it a function? Yes

4 0

3 years ago

Each cube in the prism is one cubic unit.

Ksivusya [100]

Answer:

all you do is 5x3x6
LengthxWidthxHeight

5x3x9 is 90

Step-by-step explanation:

90 units³

3 0

2 years ago

Chloe baked 6 brownies with nuts on top and 9 brownies without nuts. What is the ratio of the number of brownies without nuts to

Brums [2.3K]

Answer:

6:9 ÷3

2:3

Step-by-step explanation:

1st write the ratio then simplify it with dividing with the Highest common factor on both sides

6 0

3 years ago

4/5 n = 9/10solve n