Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 3% simple interest.

Correct Answer  $7280

Solution & Explanation

Solution

Given,

Principal (P) = $5600

Rate of Simple Interest (SI) = 3%

Time (t) = 10 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) = $5600 × 3% × 10

= $5600 ׳/₁₀₀ × 10

= ^{5600 × 3 × 10}/₁₀₀

= ^{16800 × 10}/₁₀₀

= ¹⁶⁸⁰⁰⁰/₁₀₀

= $1680

Thus, Simple Interest = $1680

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 = $5600 + $1680

= $7280

Thus, Amount to be paid = $7280 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 = $5600

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5600 + ($5600 × 3% × 10)

= $5600 + ($5600 ׳/₁₀₀ × 10)

= $5600 + (^{5600 × 3 × 10}/₁₀₀)

= $5600 + (^{16800 × 10}/₁₀₀)

= $5600 + (¹⁶⁸⁰⁰⁰/₁₀₀)

= $5600 + $1680 = $7280

Thus, Amount (A) to be paid = $7280 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 $5600, the simple interest in 1 year

= ³/₁₀₀ × 5600

= ^{3 × 5600}/₁₀₀

= ¹⁶⁸⁰⁰/₁₀₀ = $168

Thus, simple interest for 1 year = $168

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $168 × 10 = $1680

Thus, Simple Interest (SI) = $1680

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5600 + $1680

= $7280

Thus, Amount to be paid = $7280 Answer

Similar Questions

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

(2) What amount does Richard have to pay after 5 years if he takes a loan of $3600 at 2% simple interest?

(3) Find the amount to be paid if Thomas borrowed a sum of $5800 at 9% simple interest for 7 years.

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

(5) What amount does Charles have to pay after 6 years if he takes a loan of $3900 at 10% simple interest?

(6) What amount will be due after 2 years if Donald borrowed a sum of $3750 at a 4% simple interest?

(7) Mark took a loan of $6800 at the rate of 10% simple interest per annum. If he paid an amount of $11560 to clear the loan, then find the time period of the loan.

(8) Susan took a loan of $5300 at the rate of 9% simple interest per annum. If he paid an amount of $8162 to clear the loan, then find the time period of the loan.

(9) Christopher had to pay $4240 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(10) Susan took a loan of $5300 at the rate of 9% simple interest per annum. If he paid an amount of $8639 to clear the loan, then find the time period of the loan.