Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 5% simple interest.

Correct Answer  $7612.5

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 5%

Time (t) = 9 years

Thus, Amount (A) = ?

The Rate of Interest is always calculated per annum, i.e. per year.

Thus, here 5% simple interest means, Rate of Simple Interest (SI) is 5% per annum.

Method (1) Using Formula

Calculation of Simple Interest

Formula to Calculate Simple Interest

Simple Interest (SI) = Principal × Rate × Time

Thus, Simple Interest (SI) = $5250 × 5% × 9

= $5250 ×⁵/₁₀₀ × 9

= ^{5250 × 5 × 9}/₁₀₀

= ^{26250 × 9}/₁₀₀

= ²³⁶²⁵⁰/₁₀₀

= $2362.5

Thus, Simple Interest = $2362.5

Calculation of Amount

The total money paid to the lender by a borrower is called the Amount.

In other words, sum of priciple and interest is called the Amount.

Formula to Calculate the Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $2362.5

= $7612.5

Thus, Amount to be paid = $7612.5 Answer

Method (2)

Calculation of Amount when Principal, Rate of Simple Interest and Time are given

Calculation of Amount directly using Principal, SI, and Time

Formula to calculate the Amount

Amount (A) = Principal (P) + Principal(P) × Rate of Interest (SI) × Time (t)

⇒ A = P + PRT

Here in the question, P = $5250

Rate of Simple Interest (SI) or (R) = 5%

And, Time (t) = 9 years

Thus, Amount (A)

= $5250 + ($5250 × 5% × 9)

= $5250 + ($5250 ×⁵/₁₀₀ × 9)

= $5250 + (^{5250 × 5 × 9}/₁₀₀)

= $5250 + (^{26250 × 9}/₁₀₀)

= $5250 + (²³⁶²⁵⁰/₁₀₀)

= $5250 + $2362.5 = $7612.5

Thus, Amount (A) to be paid = $7612.5 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 5%

This, means, $5 per $100 per year

∵ For $100, the simple interest for 1 year = $5

∴ For $1, the simple interest for 1 year = ⁵/₁₀₀

∴ For $5250, the simple interest in 1 year

= ⁵/₁₀₀ × 5250

= ^{5 × 5250}/₁₀₀

= ²⁶²⁵⁰/₁₀₀ = $262.5

Thus, simple interest for 1 year = $262.5

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $262.5 × 9 = $2362.5

Thus, Simple Interest (SI) = $2362.5

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $2362.5

= $7612.5

Thus, Amount to be paid = $7612.5 Answer

Similar Questions

(1) What amount will be due after 2 years if John borrowed a sum of $3100 at a 5% simple interest?

(2) Calculate the amount due if Joseph borrowed a sum of $3700 at 6% simple interest for 3 years.

(3) Calculate the amount due after 10 years if Elizabeth borrowed a sum of $5450 at a rate of 10% simple interest.

(4) How much loan did Kimberly borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7647.5 to clear it?

(5) Calculate the amount due after 9 years if Jessica borrowed a sum of $5750 at a rate of 3% simple interest.

(6) What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 10% simple interest?

(7) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $9828 to clear the loan, then find the time period of the loan.

(8) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $10269 to clear the loan, then find the time period of the loan.

(9) James had to pay $3180 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(10) Calculate the amount due if Mary borrowed a sum of $3050 at 4% simple interest for 4 years.