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2 years ago

Rita answered 45 questions correctly on her latest math test. She earned 75% on that test. How many questions were on the test?

Mathematics

2 answers:

Ann [662]2 years ago

8 0

3/4ths = 45 questions think quarters

45/3=15

so if you add the last 1/4 to 3/4 you get one whole

45+15=60

60 total questions

marishachu [46]2 years ago

4 0

60 questions

45/60 = 75%

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An automobile manufacturer has given its van a 59.5 miles/gallon (MPG) rating. An independent testing firm has been contracted t

LekaFEV [45]

Answer:

The pvalue of the test is 0.0124 < 0.1, which means that there is sufficient evidence at the 0.1 level to support the testing firm's claim.

Step-by-step explanation:

An automobile manufacturer has given its van a 59.5 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the actual MPG for this van since it is believed that the van has an incorrect manufacturer's MPG rating:

At the null hypothesis, we test if the mean is the same, that is:

$H_0: \mu = 59.5$

At the alternate hypothesis, we test that it is different, that is:

$H_a: \mu \neq 59.5$

The test statistic is:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

In which X is the sample mean, $\mu$ is the value tested at the null hypothesis, $\sigma$ is the standard deviation and n is the size of the sample.

59.5 is tested at the null hypothesis:

This means that $\mu = 59.5$

After testing 250 vans, they found a mean MPG of 59.2. Assume the population standard deviation is known to be 1.9.

This means that $n = 250, X = 59.2, \sigma = 1.9$

Value of the test statistic:

$z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$

$z = \frac{59.2 - 59.5}{\frac{1.9}{\sqrt{250}}}$

$z = -2.5$

Pvalue of the test and decision:

The pvalue of the test is the probability of finding a mean that differs from 59.5 by at least 0.3, which is P(|Z|>-2.5), which is 2 multiplied by the pvalue of Z = -2.5.

Looking at the z-table, Z = -2.5 has a pvalue of 0.0062

2*0.0062 = 0.0124

The pvalue of the test is 0.0124 < 0.1, which means that there is sufficient evidence at the 0.1 level to support the testing firm's claim.

5 0

2 years ago

If 'a' is a number lying between 0 and 1. then which of the following is in increasing order? a) a², a, √a b) a √a ,a² c) a²,√a,

viktelen [127]

Step-by-step explanation:

None of these,

a(under root),a, a(square)

this is the correct answer

5 0

3 years ago

Read 2 more answers

The table shows the number of cups of water required when cooking different amounts of rice.

Harman [31]

Answer-

The amount of water is the dependent value.

Solution-

Plotting the graph from the given data points, it comes out to be a straight line with positive slope. So, both the variables i.e amount of rice and amount of water are in a linear relationship. They are directly proportional to each other.

As the amount of rice increases, the water needed to cook the rice also increases. Plotting a graph taking amount of rice in abscissa and amount of water in ordinate, a straight line was obtained.

Here, amount of rice is the independent variable and amount of water is dependent variable as it depends on the amount of rice.

3 0

3 years ago

two mechanics worked on a car. The first mechanic worked for 10 hrs, and the second mechanic worked for 5 hours. Together they c

soldier1979 [14.2K]

Answer:

The first mechanic $90/hour and the second charged $70/hour

Step-by-step explanation:

Lets start off by letting x be the first mechanics rate and y being the second mechanics rate. We know that the first mechanic worked 5 hours and that the second mechanic worked 10 hours and together they charged 1150. An equation to express this would be:

5x+10y = 1150

We also know that together they charged 160/per hour. An equation to express this would be:

x+y = 160

Now we can solve the second equation for x or the first mechanics rate.

x+y = 160

x = 160 - y

Now that we have an expression for x we can plug that back into the first equation and solve for y or how much the second mechanic charged.

5x+10y=1150 plug in x =160-y

5(160-y)+10y=1150 Distribute

800 -5y+10y = 1150 Combine like terms

800 +5y = 1150 Subtract 800 from both sides

5y = 350 divide by 5

y = 70

So we know that the second mechanic charged $70/hour. We also know that(from our work before) that the first mechanic charges $160 - the rate the second mechanic charged. We know that's $70/hour so we can plug in and solve for the first rate.

x = 160-y

x = 160-70

x = 90

So we know that the first mechanic charged $90/hour and the second mechanic charged $70/hour.

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3 years ago

What is the graph of the solution to the following compound inequality 3-x>=2 or 4x+2>=10

Luba_88 [7]

6 cause i dont really know

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3 years ago