Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Joseph borrowed a sum of $5700 at a rate of 3% simple interest.

Correct Answer  $7239

Solution & Explanation

Solution

Given,

Principal (P) = $5700

Rate of Simple Interest (SI) = 3%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $5700 × 3% × 9

= $5700 ׳/₁₀₀ × 9

= ^{5700 × 3 × 9}/₁₀₀

= ^{17100 × 9}/₁₀₀

= ¹⁵³⁹⁰⁰/₁₀₀

= $1539

Thus, Simple Interest = $1539

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 = $5700 + $1539

= $7239

Thus, Amount to be paid = $7239 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 = $5700

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 9 years

Thus, Amount (A)

= $5700 + ($5700 × 3% × 9)

= $5700 + ($5700 ׳/₁₀₀ × 9)

= $5700 + (^{5700 × 3 × 9}/₁₀₀)

= $5700 + (^{17100 × 9}/₁₀₀)

= $5700 + (¹⁵³⁹⁰⁰/₁₀₀)

= $5700 + $1539 = $7239

Thus, Amount (A) to be paid = $7239 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = ³/₁₀₀

∴ For $5700, the simple interest in 1 year

= ³/₁₀₀ × 5700

= ^{3 × 5700}/₁₀₀

= ¹⁷¹⁰⁰/₁₀₀ = $171

Thus, simple interest for 1 year = $171

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $171 × 9 = $1539

Thus, Simple Interest (SI) = $1539

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5700 + $1539

= $7239

Thus, Amount to be paid = $7239 Answer

Similar Questions

(1) Joseph had to pay $4144 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(2) What amount does Joseph have to pay after 6 years if he takes a loan of $3700 at 10% simple interest?

(3) How much loan did Betty borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7187.5 to clear it?

(4) What amount will be due after 2 years if Paul borrowed a sum of $3850 at a 8% simple interest?

(5) If Joshua paid $5292 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(6) What amount does Thomas have to pay after 5 years if he takes a loan of $3800 at 6% simple interest?

(7) What amount does Richard have to pay after 5 years if he takes a loan of $3600 at 7% simple interest?

(8) Find the amount to be paid if Charles borrowed a sum of $5900 at 5% simple interest for 7 years.

(9) Michael took a loan of $4600 at the rate of 8% simple interest per annum. If he paid an amount of $7176 to clear the loan, then find the time period of the loan.

(10) Find the amount to be paid if Charles borrowed a sum of $5900 at 6% simple interest for 7 years.