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3 years ago

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Alexis Brian and Carli collect graphic novels, Brian has 5 more graphic novels then Alexis and Carli has twice as many as Alexis

. Define a variable and write an expression to represent the total number of graphic novels for the three people

1 answer:

kkurt [141]3 years ago

4 0

According to Google, a Variable is <span>any factor, trait, or condition that can exist in differing amounts or types. If you type in variable in the Google search bar, it will give you the definition in a little box at the very top of the page :).
</span>

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To solve X/0.4 = 10, you would: Add 0.4 Subtract 0.4 Multiply 0.4 Divide by 0.4

Mrac [35]

Multiply by 0.4 on both sides to cancel the original 0.4 and change the 10

8 0

3 years ago

A quality control expert at LIFE batteries wants to test their new batteries. The design engineer claims they have a variance of

iris [78.8K]

Answer:

The probability that the mean battery life would be greater than 533.2 minutes (in a sample of 75 batteries) is $\\ P(z>0.48) = P(x>533.2) = 0.3156$

Step-by-step explanation:

The main thing we have to take into account in this question is that we are about to find the probability of a <em>sample mean</em>. The distribution for <em>sample means</em> follows a <em>normal distribution</em> with mean $\\ \mu$ and standard deviation $\\ \frac{\sigma}{\sqrt{n}}$ . Mathematically

$\\ \overline{x} \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

For values of the sample $\\ n \ge 30$ , no matter the distribution the data come from.

And the variable <em>z</em> follows a <em>standard normal distribution</em>, and, as we can remember, this distribution has a mean = 0 and a standard deviation = 1. Mathematically

$\\ z = \frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$ [1]

That is

$\\ z \sim N(0, 1)$

We have a variance of 3364. That is, a <em>standard deviation</em> of

$\\ \sigma^2 = 3364; \sigma = \sqrt{3364} = 58$

The population mean is

$\\ \mu = 530$

The sample size is $\\ n = 75$

The sample mean is $\\ \overline{x} = 533.2$

With all this information, we can solve the question

The probability that the mean battery life would be greater than 533.2 minutes

Using equation [1]

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

$\\ z = \frac{533.2 - 530}{\frac{58}{\sqrt{75}}}$

$\\ z = \frac{3.2}{\frac{58}{8.66025}}$

$\\ z = \frac{3.2}{6.69726}$

$\\ z = 0.47780$

With this value of z we can consult a <em>cumulative standard normal table</em> (or use some statistic program) to find the cumulative probability for <em>z</em> (and remember that this variable follows a standard normal distribution).

Most standard normal tables have values for z for only two decimals, so we can round the previous value for z as z = 0.48.

Then

$\\ P(z$

However, in the question we are asked for $\\ P(z>0.48) = P(x>533.2)$ . As well as all normal distributions, the standard normal distribution is symmetrical around the mean, and we have

$\\ P(z>0.48) = 1 - P(z$

Thus

$\\ P(z>0.48) = 1 - 0.68439$

$\\ P(z>0.48) = 0.31561$

Rounding to four decimal places, we have

$\\ P(z>0.48) = 0.3156$

So, the probability that the mean battery life would be greater than 533.2 minutes is (in a sample of 75 batteries) $\\ P(z>0.48) = P(x>533.2) = 0.3156$ .

5 0

3 years ago

Marcus has a bag of cat food that contains 22 1/2 cups.if he feeds his cats a total of 3/4 cup of food per day,how many days wil

Korvikt [17]

Answer:

30 days.

Step-by-step explanation:

22 1/2 = 45/2 since 22*2+1 = 45, then divide that by 3/4 which, in reality, means multiply by 4/3. I then cross-multiplied by finding the GCF of the diagonal pairs. I hope this helped! Please mark Brainliest if it did.

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3 years ago

Which statement describes the foreign exchange rate?

prohojiy [21]

The foreign exchange rate is a rate at which one currency is exchanged for another, and it exists because not all currencies are worth the same. In short, money of one country is worth more than money of a different country.

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2 years ago

Bru.h i'm my room and my sister walked in naked and said come to her room what do i do

kvv77 [185]

Call animal control on her

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2 years ago

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