GMAT Math : Calculating simple interest

年代tudy concepts, example questions & explanations for GMAT Math

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Example Questions

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Example Question #1 :Interest Problems

Grandpa Jack wants to help pay for college for his grandson, Little Jack. Little Jack is currently 8 years old. Grandpa Jack makes a one-time deposit into an account that earns simple interest every year. Grandpa Jack invests $10,000 now and in ten years, that will grow to $15,000. What rate of simple interest did Grandpa Jack receive?

Possible Answers:

4%

6%

2%

3%

5%

Correct answer:

5%

Explanation:

To calculate simple interest, the formula is

wherestands for Future Value,stands for Present Value,stands for the interest rate, andstands for the number of periods (in this case years). So plugging in,

年代olving this we get

or 5%

ALTERNATE SOLUTION:

Another way of finding this is to calculate the amount of interest per year. Since this is simple interest, Grandpa Jack earns the same amount of interest per year. The total interest earned is 15,000-10,000= 5,000. $5,000 over 10 years, equates to $500 per year. $500 divided by the original $10,000 is .05, or 5%.

Example Question #2 :Interest Problems

How much interest would an investment yield if the principal ofis invested foryears at asimple interest?

Possible Answers:

Correct answer:

Explanation:

Example Question #3 :Interest Problems

What rate does Johnny need if he would like to yieldin interest from a principal ofinyears?

Possible Answers:

Correct answer:

Explanation:

Example Question #1 :Interest Problems

A bank offers a business a loan in the amount of $13,000 with a simple annual interest rate of 9%. How much will the business owe the bank after 3 years?

Possible Answers:

Correct answer:

Explanation:

The accrual of simple interest can be found in two steps. First, multiply the principal amount by the interest rate. Second, multiply that result by the number of years during which interest will accrue.

The question asks for the total amount that the business will owe the bank, so we must add the interest accrued to the principal amount.

Example Question #5 :Interest Problems

John hasto invest foryears forreturn. How much simple interest will his investment yield?

Possible Answers:

Correct answer:

Explanation:

年代imple interest formula:

Example Question #6 :Interest Problems

How many years would it take Marissa to makein interest using a simple interest investment ofin principal at 5% return?

Possible Answers:

Correct answer:

Explanation:

年代imple interest formula is:

Therefore, solving for the time factor:

Example Question #7 :Interest Problems

Using the simple interest formula, what initial investment does Terry have to make to earnin interest if there is anreturn foryears?

Possible Answers:

Correct answer:

Explanation:

年代imple interest formula:

Therefore, solving for the principal factor in the equation:

Example Question #8 :Interest Problems

What return does Florence have to yield in order to makein interest off of a simple investment offoryears?

Possible Answers:

Correct answer:

Explanation:

年代imple interest formula:

Therefore, solving for the rate factor in the equation:

Example Question #9 :Interest Problems

Jesse hasto invest foryears forreturn. How much simple interest will his investment yield?

Possible Answers:

Correct answer:

Explanation:

年代imple interest formula:

Example Question #10 :Interest Problems

How many years would it take Julissa to makein interest using a simple interest investment ofat areturn?

Possible Answers:

Correct answer:

Explanation:

年代imple interest formula is:

Therefore, solving for the time factor:

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