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2 years ago

Help pls It’s math models

Mathematics

1 answer:

navik [9.2K]2 years ago

6 0

Answer: C. 12/28

Step-by-step explanation:

When multiplying fractions, you multiply the numerator by the second fraction's numerator (a numerator is the top number in the fraction), and the denominator (a denominator is the bottom number in the fraction) by the second fraction's denominator.

For example:

4 (numerator of fraction 1) x 3 (numerator of fraction 2) = 12

4 (denominator of fraction 1) x 7 (denominator of fraction 2) = 28

So, the final product would be 12/28.

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Some one please HeLp and explain

mihalych1998 [28]

Answer:

2nd option

Step-by-step explanation:

You're goal is to isolate b by itself. The only part you need to worry about is the equation, the rest of the word problem is irrelevant.

The whole process of solving this is to do PEMDAS in reverse.

So first add/subtract all the values that does not have a b attach to it to the other side.

then multiply/divide all the values that is not a b to get the b-value by itself

3 0

3 years ago

A boy leaves on a bicycle trip at the rate of 8 mph. One hour later the father, realizing that his son forgot his camping

KatRina [158]

Answer:

40 mph

Step-by-step explanation:

One hour includes 60 minutes

8/60=0.13(3 repeating)

You only need 15 minutes of time

0.13(3 repeating)*15=2

8+2=10 miles

15 minutes is 1/4 of an hour

10*4=40 mph

6 0

2 years ago

In a survey conducted by the Gallup Organization, 1100 adult Americans were asked how many hours they worked in the previous we

const2013 [10]

Answer:

1) Increase the sample size

2) Decrease the confidence level

Step-by-step explanation:

The 95% confidence interval built for a sample size of 1100 adult Americans on how much they worked in previous week is:

42.7 to 44.5

We have to provide 2 recommendations on how to decrease the margin of Error. Margin of error is calculated as:

$M.E=z_{\frac{\alpha}{2} } \times \frac{\sigma}{\sqrt{n}}$

Here,

$z_{\frac{\alpha}{2} }$ is the critical z-value which depends on the confidence level. Higher the confidence level, higher will be the value of critical z and vice versa.

$\sigma$ is the population standard deviation, which will be a constant term and n is the sample size. Since n is in the denominator, increasing the value of n will decrease the value of Margin of Error.

Therefore, the 2 recommendations to decrease the Margin of error for the given case are:

Increase the sample size and make it more than 1100
Decrease the confidence level and make it lesser than 95%.

7 0

3 years ago

Two brands of AAA batteries are tested in order to compare their voltage. The data summary can be found below. Find the 93% conf

kobusy [5.1K]

Answer:

$(\bar X_1 -\bar X_2) \pm z_{\alpha/2} \sqrt{\frac{s^2_1}{n_1}+\frac{s^2_}{n_2}}$

And replacing we got:

$(9.2 -8.8) - 1.811 \sqrt{\frac{0.3^2}{27}+\frac{0.1^2}{30}}= 0.2903$

$(9.2 -8.8) + 1.811 \sqrt{\frac{0.3^2}{27}+\frac{0.1^2}{30}}= 0.5097$

And the confidence interval for the difference of means would be given by:

$0.2903 \leq \mu_1 -\mu_2 \leq 0.5097$

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

We have the following data given:

$\bar X_1 = 9.2 , \bar X_2 = 8.8, \sigma_1= 0.3, n_1 = 27, \sigma_2 = 0.1, n_2 = 30$

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 93% of confidence, our significance level would be given by $\alpha=1-0.93=0.07$ and $\alpha/2 =0.035$ . And the critical value would be given by:

$z_{\alpha/2}=-1.811, z_{1-\alpha/2}=1.811$

The confidence interval is given by:

$(\bar X_1 -\bar X_2) \pm z_{\alpha/2} \sqrt{\frac{s^2_1}{n_1}+\frac{s^2_}{n_2}}$

And replacing we got:

$(9.2 -8.8) - 1.811 \sqrt{\frac{0.3^2}{27}+\frac{0.1^2}{30}}= 0.2903$

$(9.2 -8.8) + 1.811 \sqrt{\frac{0.3^2}{27}+\frac{0.1^2}{30}}= 0.5097$

And the confidence interval for the difference of means would be given by:

$0.2903 \leq \mu_1 -\mu_2 \leq 0.5097$

4 0

3 years ago

8(c-9)=6(2c-12)-4c How to solve questions like this

Gennadij [26K]

Step 1-Distributive Property
8c-72=12c-2-4c
Step 2-Combine Like Terms
8c-72=8c-2
Step 3-Divide both 8c's by 8
-72=-2 -72 does NOT equal -2 so this equation has no solution...Hope this helps have a great Day!!!

3 0

3 years ago