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3 years ago

3. When 25 is added to 7 times a number, the result is 81. Find the number.

Mathematics

1 answer:

Dominik [7]3 years ago

4 0

Answer:

3. 2.5

4. $5 per candy bar

5. You mowed 6 lawns

6. 15.66 is the number

7. 13 weeks

8. 135 students came

9. 12

Step-by-step explanation:

3. 25+7= 32.

81/32= 2.5

4. 23-3= 20

20/4= 5

5. 155-35=120

120/20=6

6. 10-4 = 6

94/6=15.66

(not 100% sure about this one)

7. 200-161=39

39/3=13

8. 975-300=675

675/5=135

9. 36-12=24

36/3= 12

(not 100% sure about this one)

Bonus: Sorry I don't know

I hope I can help! Also next time do each question one by one so other people can answer and not answer all of them if they don't know one.

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10.

Kay [80]

Answer:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.535 \leq \sigma^2 \leq 7.602$

Now we just take square root on both sides of the interval and we got:

$2.2 \leq \sigma \leq 2.8$

And the best option would be:

A. 2.2 < σ < 2.8

Step-by-step explanation:

Information provided

$\bar X=32.1$ represent the sample mean

$\mu$ population mean

s=2.4 represent the sample standard deviation

n=83 represent the sample size

Confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

The degrees of freedom are given by:

$df=n-1=83-1=82$

The Confidence is given by 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , the critical values for this case are:

$\chi^2_{\alpha/2}=62.132$

$\chi^2_{1- \alpha/2}=104.139$

And replacing into the formula for the interval we got:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.535 \leq \sigma^2 \leq 7.602$

Now we just take square root on both sides of the interval and we got:

$2.2 \leq \sigma \leq 2.8$

And the best option would be:

A. 2.2 < σ < 2.8

3 0

3 years ago

Lois says any addition equation where the addends are all the same can be written as a multiplication equation. Is Lois correct

USPshnik [31]

Lois is correct. This is because multiplication is repeated addition. It means that when your addends are just the same number but added several times, the sum is just equivalent to the product of that number times the number of times it was added. For example, 4+4+4 = 4×3 = 12.

6 0

3 years ago

Beau has an annual adjusted gross income of $89,750. He is applying for a mortgage loan that would have a monthly payment of $1,

ozzi

Answer:

C. 21%

Step-by-step explanation:

Please kindly check the attached file for explanation.

8 0

4 years ago

Read 2 more answers

A coffee shop spends $408 for an order of 17 cases of paper cups. If the coffee shop adds 5 more cases of paper cups to the orde

-Dominant- [34]

Answer:

$528

Step-by-step explanation:

If cost is proportional to order quantity, the cost for 17+5 = 22 cases of cups will be 22/17 times the cost for 17 cases:

(22/17)($408) = $528

7 0

4 years ago

The quotient of 7/8 / 3/8

aleksandr82 [10.1K]

Answer:

7/3

Step-by-step explanation:

Keep Change Flip -KCF (not to be confused with kfc )

7/8 x 8/3

Keep Change Flip in other words, keep the first fraction change from division to multiplication (since multiplication is the opposite of division) and flip the second fraction

8 0

3 years ago