Simple Interest
Math MCQs

Question :    Find the amount to be paid if Jennifer borrowed a sum of $5250 at 9% simple interest for 7 years.

Correct Answer  $8557.5

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 9%

Time (t) = 7 years

Thus, Amount (A) = ?

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

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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 × 9% × 7

= $5250 ×⁹/₁₀₀ × 7

= ^{5250 × 9 × 7}/₁₀₀

= ^{47250 × 7}/₁₀₀

= ³³⁰⁷⁵⁰/₁₀₀

= $3307.5

Thus, Simple Interest = $3307.5

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 + $3307.5

= $8557.5

Thus, Amount to be paid = $8557.5 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) = 9%

And, Time (t) = 7 years

Thus, Amount (A)

= $5250 + ($5250 × 9% × 7)

= $5250 + ($5250 ×⁹/₁₀₀ × 7)

= $5250 + (^{5250 × 9 × 7}/₁₀₀)

= $5250 + (^{47250 × 7}/₁₀₀)

= $5250 + (³³⁰⁷⁵⁰/₁₀₀)

= $5250 + $3307.5 = $8557.5

Thus, Amount (A) to be paid = $8557.5 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = ⁹/₁₀₀

∴ For $5250, the simple interest in 1 year

= ⁹/₁₀₀ × 5250

= ^{9 × 5250}/₁₀₀

= ⁴⁷²⁵⁰/₁₀₀ = $472.5

Thus, simple interest for 1 year = $472.5

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $472.5 × 7 = $3307.5

Thus, Simple Interest (SI) = $3307.5

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $3307.5

= $8557.5

Thus, Amount to be paid = $8557.5 Answer

Similar Questions

(1) Calculate the amount due after 10 years if Mary borrowed a sum of $5050 at a rate of 3% simple interest.

(2) If Michael paid $3696 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(3) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 6% simple interest.

(4) Calculate the amount due after 9 years if Elizabeth borrowed a sum of $5450 at a rate of 5% simple interest.

(5) If Christopher borrowed $4000 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(6) Sandra took a loan of $6900 at the rate of 9% simple interest per annum. If he paid an amount of $11247 to clear the loan, then find the time period of the loan.

(7) Elizabeth took a loan of $4900 at the rate of 10% simple interest per annum. If he paid an amount of $8330 to clear the loan, then find the time period of the loan.

(8) What amount does Richard have to pay after 5 years if he takes a loan of $3600 at 6% simple interest?

(9) What amount does David have to pay after 6 years if he takes a loan of $3400 at 7% simple interest?

(10) What amount does John have to pay after 5 years if he takes a loan of $3200 at 5% simple interest?