The sum of two numbers is twice their difference. The larger number is 2 more than twice the smaller

The distribution of income tax refunds follow an approximate normal distribution with a mean of $7010 and a standard deviation o

Andrej [43]

Answer:

A refund must be above $7,139 before it is audited.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 7010, standard deviation = 43.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

The empirical rule is symmetric, which means that the lowest (100-99.7)/2 = 0.15% is at least 3 standard deviations below the mean, and the upper 0.15% is at least 3 standard deviations above the mean.

Use the Empirical Rule to determine approximately above what dollar value must a refund be before it is audited.

3 standard deviations above the mean, so:

7010 + 3*43 = 7139.

A refund must be above $7,139 before it is audited.

5 0

3 years ago

What is the point of intersection of the x-axis and the y-axis called

tester [92]

That is called the Origin , where the number 0 is.

6 0

3 years ago

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She worked a total of 15 hours. If she makes $15 per hour tutoring and $9 per hour at the grocery store and made a total of $159

Ugo [173]

Answer:

11 hours she worked at the grocery store

Step-by-step explanation:

assuming,

the number of hours worked at tutoring = x

the number of hours worked at grocery store = y

which means,

the amount she made at tutoring = x* $15

the amount she made at grocery store = y*$9

we have 2 equations

total number of hours

1) x+y= 15

total amount she earned

2) x* $15+ y* $9= $159

From equation 1

x+y= 15

x=15-y

we replace this x value in equation 2

x* $15+ y* $9= $159

(15-y)* $15+ y* $9= $159

(15*15)- 15y+9y=159

225-6y=159

225-159=6y

66=6y

66/6=y

11=y the number of hours she worked at grocery store.

we place y=11 in our derived x equation

x=15-y

x=15-11

x=4 the number of hours she worked at tutoring.

3 0

3 years ago

To estimate the number of people in Springfield, population 10,000, who have a swimming pool in their backyard, 250 people were

Andrei [34K]

Answer:

2400 people

Step-by-step explanation:

Let x be the number of people who had a swimming pool in the population of 10,000,

Thus, the ratio of people who had swimming pool to the total population = $\frac{x}{10000}$

Since, out of 250 people 60 had swimming pool,

So, the ratio of the people who had swimming pool to the total population = $\frac{60}{250}$

$\because \frac{x}{10000}=\frac{60}{250}$

$\implies 250x=600000$

$\implies x=\frac{600000}{250}=2400$

Hence, 2400 people in the city might one expect to have a swimming pool.

First option is correct.

8 0

3 years ago

Which is bigger 13% or 3/25?

belka [17]

Change 13% as a fraction. It will be 13/100

Now, which is bigger? 13/100 or 3/25
Cross multiply and 13/100 is bigger.

13 3
___ X ____
100 25

13×25=325 and 3×100=300. Now you know 13/100 is bigger.

The answer is 13/100

6 0

3 years ago

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