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April wants to borrow $400 from her father and is willing to pay $11 in interest. Her father wants to charge an interest rate of 3 %. Howlong can April keep the money?

User Griffin
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2 Answers

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27 votes

Final answer:

To determine how long April can borrow $400 at an interest rate of 3% to pay $11 in interest, use the simple interest formula. The result is approximately 11/12 years, or about 11 months.

Step-by-step explanation:

April wants to borrow $400 and is willing to pay $11 in interest. Her father wants to charge her an interest rate of 3%. The question essentially asks how long it would take to accrue $11 in interest at this rate, which is a simple interest problem.

To find the time, we use the simple interest formula: Interest = Principal × Rate × Time. Here, the interest is $11, the principal is $400, and the rate is 3% per year, which can be written as 0.03. We will solve for time (T) as follows: $11 = $400 × 0.03 × T.

Dividing both sides by $400 × 0.03, we get: T = $11 / ($400 × 0.03). T = $11 / $12. T = 11/12 years.

Therefore, April can keep the money for 11/12 years, or approximately 0.9167 years, which is about 11 months.

User Julien L
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18 votes
18 votes

Given that

April borrowed $400 (which is the principal)

He is willing to pay back $11 interest (this is the simple interest)

The father want an interest rate of 3% (this is the rate)

Thus, we want to find time

Solution

Recall the simple interest (S.I) formula


\text{S}I=(PRT)/(100)

As explained above P =$400, R = 3%, T =?, S.I = 11

We put the parameters into the formula and we solve for T


\begin{gathered} \text{S}I=(PRT)/(100) \\ 11=(400*3* T)/(100) \\ 11=4*3* T \\ 11=12T \\ \therefore\text{ T =}(11)/(12)years \end{gathered}

Therefore, April can keep the money for 11 months or 11/12 years

User Qqtf
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