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2 years ago

What simple interest rate is needed for $1000 to grow to $1071.25 in 9 months?

Mathematics

2 answers:

BlackZzzverrR [31]2 years ago

3 0

Answer:

9.5%

Step-by-step explanation:

Use the formula I = Prt

I is the interest (unknown), P is the principal (1000), rate is the percent (unknown), and t is time in years (9/12).

9 months is a fraction of a year. There are 12 months in a year, so our fraction is 9/12. You can reduce this fraction by dividing by 3. The fraction reduced is 3/4. You can also use the decimal which is .75.

First we need to solve how much interest we earned. 1071.25 is the balance, so we need to subtract the principal from the balance.

1071.25 - 1000 = 71.25

Plug the numbers in to the formula. We are solving for r.

71.25 = 1000(.75)r

71.25 = 750r

71.25/750 = 750r/750

r = 0.095

Convert the decimal to a percent by moving the decimal two places right.

0.095 = 9.5%

Alex2 years ago

3 0

Use the formula | = Prt
I is the interest (unknown), P is the principal
(1000), rate is the percent (unknown), and t is
time in years (9/12).
9 months is a fraction of a year. There are 12
months in a year, so our fraction is 9/12. You can
reduce this fraction by dividing by 3. The fraction
reduced is 3/4. You can also use the decimal
which is .75.
First we need to solve how much interest we
earned. 1071.25 is the balance, so we need to
subtract the principal from the balance.
1071.25 - 1000 = 71.25
Plug the numbers in to the formula. We are
solving for r.
71.25 = 1000(.75)r
71.25 = 750r
71.25/750 = 750r/750
r= 0.095
Convert the decimal to a percent by moving the

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Answer: C

Step-by-step explanation:

1 1/8 = 1.125

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3 years ago

How much fabric is needed to make a tent in the shape of a triangular prism with the following measures?

Contact [7]

Answer:

The fabric needs 196.4 ft²

Step-by-step explanation:

∵ The tent formed formed from 4 faces

two equilateral triangles with side length 7 ft

two rectangles with dimensions 11 ft and 7 ft

∵ Area equilateral Δ = 1/4 S²√3

∵ Area rectangle = L × W

∴ The area of the prism = 2 × 1/4 × (7)²√3 + 2 × 7 × 11

= 196.4 ft²

Note:

If you find the area of the triangle by the rule 1/2 × base × height

∴ Area Δ = 1/2 × (7) × 6 = 21 ft²

∴ Area tent = 2 × 21 + 2 × 77 = 196 ft²

Two answer very closed

8 0

3 years ago

Read 2 more answers

The percentage of body fat of a random sample of 36 men aged 20 to 29 found a sample mean of 14.42. Find a 95% confidence interv

Rina8888 [55]

Answer:

$14.42-1.96\frac{6.95}{\sqrt{36}}=12.150$

$14.42+ 1.96\frac{6.95}{\sqrt{36}}=16.690$

So on this case the 95% confidence interval would be given by (12.150;16.690)

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X=14.42$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=6.95$ represent the population standard deviation

n=36 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$