Simple Interest
Math MCQs

Question :    Find the amount to be paid if Jennifer borrowed a sum of $5250 at 9% simple interest for 8 years.

Correct Answer  $9030

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 9%

Time (t) = 8 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% × 8

= $5250 ×⁹/₁₀₀ × 8

= ^{5250 × 9 × 8}/₁₀₀

= ^{47250 × 8}/₁₀₀

= ³⁷⁸⁰⁰⁰/₁₀₀

= $3780

Thus, Simple Interest = $3780

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 + $3780

= $9030

Thus, Amount to be paid = $9030 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) = 8 years

Thus, Amount (A)

= $5250 + ($5250 × 9% × 8)

= $5250 + ($5250 ×⁹/₁₀₀ × 8)

= $5250 + (^{5250 × 9 × 8}/₁₀₀)

= $5250 + (^{47250 × 8}/₁₀₀)

= $5250 + (³⁷⁸⁰⁰⁰/₁₀₀)

= $5250 + $3780 = $9030

Thus, Amount (A) to be paid = $9030 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 8 years

= Simple interest for 1 year × 8

= $472.5 × 8 = $3780

Thus, Simple Interest (SI) = $3780

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $3780

= $9030

Thus, Amount to be paid = $9030 Answer

Similar Questions

(1) Calculate the amount due if Mary borrowed a sum of $3050 at 6% simple interest for 3 years.

(2) How much loan did Donna borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $8220 to clear it?

(3) How much loan did Dorothy borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8337.5 to clear it?

(4) How much loan did Jeffrey borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8970 to clear it?

(5) What amount does Christopher have to pay after 6 years if he takes a loan of $4000 at 5% simple interest?

(6) John had to pay $3584 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(7) What amount will be due after 2 years if Mark borrowed a sum of $3700 at a 5% simple interest?

(8) If Donna paid $5238 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(9) Sarah took a loan of $5700 at the rate of 10% simple interest per annum. If he paid an amount of $11400 to clear the loan, then find the time period of the loan.

(10) What amount does Robert have to pay after 5 years if he takes a loan of $3100 at 4% simple interest?