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3 years ago

Four times the difference of a number and seven is 32

Mathematics

1 answer:

disa [49]3 years ago

5 0

As a formula, you're saying 4*(n-7)=32

This solves to n-7 = 8, so n=15

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The mean hours of sleep that students get per night is 7 hours, the standard deviation of hours of sleep is 1.7 hours, and the d

densk [106]

Answer:

c. 3.6 and 10.4 hrs

Step-by-step explanation:

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

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

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

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

In this problem, we have that:

Mean 7, standard deviation 1.7.

For about 95% of students, nightly amount of sleep is between

7 - 2*1.7 = 7 - 3.4 = 3.6 hours

7 + 2*1.7 = 7 + 3.4 = 10.4 hours

So the correct answer is:

c. 3.6 and 10.4 hrs

5 0

3 years ago

Jim had some dimes, quarters, and nickels. First, he counted only the dimes and quarters and found that he had 9 coins. Then, he

Olegator [25]

Answer:

$1.90

Step-by-step explanation:

Represent the numbers of nickels, dimes and quarters by n, d and q.

Then: d + q = 9, or q = 9 - d.

Also, n + d = 10

Lastly, n + d + q = 15.

Let's substitute 9 - d for q in the equation immediately above:

n + d + (9 - d) = 15, or n + 9 = 15. Then n must be 6.

In summary, Jim has 6 nickels, (10 - 6) dimes and (9 - 4) quarters, or:

6 nickels, 4 dimes and 5 quarters

Thus, he has 5($0.05) + 4($0.10) + 5($0.25), or

$0.25 + $0.40 + $1.25, or $1.90

7 0

3 years ago

Assume that the Poisson distribution applies and that the mean number of aircraft accidents is 9 per month. Find P(0), the prob

Ugo [173]

Answer: 0.0001

It is unlikely to have a month with no aircraft accidents .

Step-by-step explanation:

Given : Mean number of aircraft accidents = 9 per month

The Poisson distribution formula :-

$\dfrac{e^{-\lambda}\lambda^x}{x!}$ , where $\lambda$ is the mean of the distribution.

If X = the number of aircraft accidents per month, then the probability that in a month, there will be no aircraft accidents will be :-

$\dfrac{e^{-9}(9)^0}{0!}=0.000123409804087\approx0.0001$

Hence, the probability that in a month, there will be no aircraft accidents = 0.0001

Since this is less than 0.5 , therefor it is unlikely to have a month with no aircraft accidents .

5 0

3 years ago

Simplify the expressions:

mestny [16]

Answer:

-1v

0.6y+2.1

3w-p+4

1-6x

-5x+10y+z-25

Step-by-step explanation:

Combine like terms

8 0

3 years ago

Circles M and K are congruent,arc QR is congruent to arc LN and arc OP is congruent to arc VW find y

Sladkaya [172]

The answer is -5. Just plug in -5 to check and x will equal 3.

3 0

3 years ago

Read 2 more answers