Can somebody help me with this math question?

I have to be awake at 5am and it’s about to be 12am so can someone please help me with this 7th grade math homework

finlep [7]

Step-by-step explanation:

Divide the denominator by the numerator to find the percentage

5 0

4 years ago

Life Expectancies In a study of the life expectancy of people in a certain geographic region, the mean age at death was years an

Sphinxa [80]

Answer:

The probability that the mean life expectancy of the sample is less than X years is the p-value of $Z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$ , in which $\mu$ is the mean life expectancy, $\sigma$ is the standard deviation and n is the size of the sample.

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 establishes 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.

We have:

Mean $\mu$ , standard deviation $\sigma$ .

Sample of size n:

This means that the z-score is now, by the Central Limit Theorem:

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

Find the probability that the mean life expectancy will be less than years.

The probability that the mean life expectancy of the sample is less than X years is the p-value of $Z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}$ , in which $\mu$ is the mean life expectancy, $\sigma$ is the standard deviation and n is the size of the sample.

8 0

3 years ago

5/6-1/9=?/?-?/? =13/18

daser333 [38]

15/18 - 2/18 = 13/18

Find the least common multiple of 6 and 9. The LCM is 18. In order to get 18 on the denominator with 6, you have to multiply by 3 because 6 times 3 is 18. You have to multiply 3 to the numerator, so 5 times 3 is 15. Thus, the first fraction is 15/18. To get the second, you need to find what would get you 18 on the denominator with 9. You need 2, so 9 times 2 is 18. You have to multiply 2 to the numerator, so 1 times 2 is 2. Thus, the second fraction is 2/18.

4 0

3 years ago

Please help me , btw it’s study island .

Anni [7]

a. The water in the second tank decreases at a faster rate than the water in the first tank. The initial water level in the first tank is greater than the initial water level in the second tank.

Step-by-step explanation:

Step 1:

It is given that the time remaining in first tank is given by the equation y = -10x + 80. We can get the total water in the tank by substituting x = 0 in the equation. The total volume of water in first tank is 80 litres.

Step 2:

The value of y in the equation y = -10x + 80 will be 0 when the tank is fully empty. When y = 0 , 10x = 80, so x = 8. We can conclude that the first tank empties fully in 8 minutes.

In 8 minutes 80 litres of water is emptied from first tank. So the water in the first tank decreases at rate of 80 / 8 = 10 litres per minute

Step 3:

As per the given table for the second tank, 60 litres of water remains when x =0. So the total volume of water in the second tank = 60 litres.

Step 4:

As per the given table for the second tank, the volume becomes 0 in 5 minutes. In 5 minutes 60 litres of water is emptied from second tank. So the water in second tank decreases at rate of 60 / 5 = 12 litres per minute.

Step 5:

The initial volume of water in first tank is higher. The water in second tank decreases at a faster rate than the first tank.

Step 6:

The only correct option is:

a. The water in second tank decreases at a faster rate than the water in the first tank. The initial water level in first tank is greater than the initial water level in the second tank.

5 0

3 years ago

What is 6x + 10 = 6x + 21

Akimi4 [234]

Answer:

no solution

Step-by-step explanation:

6x + 10 = 6x + 21

combine like terms

6x - 6x = 21 - 10

combine like terms

0 $\neq$ 11

no solution

5 0

4 years ago

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