Simple Interest
Math MCQs

Question :    What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 5% simple interest?

Correct Answer  $3630

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 5%

Time (t) = 2 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) = $3300 × 5% × 2

= $3300 ×⁵/₁₀₀ × 2

= ^{3300 × 5 × 2}/₁₀₀

= ^{16500 × 2}/₁₀₀

= ³³⁰⁰⁰/₁₀₀

= $330

Thus, Simple Interest = $330

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 = $3300 + $330

= $3630

Thus, Amount to be paid = $3630 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 = $3300

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

And, Time (t) = 2 years

Thus, Amount (A)

= $3300 + ($3300 × 5% × 2)

= $3300 + ($3300 ×⁵/₁₀₀ × 2)

= $3300 + (^{3300 × 5 × 2}/₁₀₀)

= $3300 + (^{16500 × 2}/₁₀₀)

= $3300 + (³³⁰⁰⁰/₁₀₀)

= $3300 + $330 = $3630

Thus, Amount (A) to be paid = $3630 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 $3300, the simple interest in 1 year

= ⁵/₁₀₀ × 3300

= ^{5 × 3300}/₁₀₀

= ¹⁶⁵⁰⁰/₁₀₀ = $165

Thus, simple interest for 1 year = $165

Therefore, simple interest for 2 years

= Simple interest for 1 year × 2

= $165 × 2 = $330

Thus, Simple Interest (SI) = $330

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $330

= $3630

Thus, Amount to be paid = $3630 Answer

Similar Questions

(1) What amount will be due after 2 years if Michael borrowed a sum of $3150 at a 9% simple interest?

(2) John had to pay $3488 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(3) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 10% simple interest.

(4) What amount will be due after 2 years if Matthew borrowed a sum of $3600 at a 9% simple interest?

(5) Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 3% simple interest.

(6) Robert took a loan of $4200 at the rate of 6% simple interest per annum. If he paid an amount of $6720 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due after 10 years if William borrowed a sum of $5500 at a rate of 6% simple interest.

(8) Daniel took a loan of $6200 at the rate of 10% simple interest per annum. If he paid an amount of $12400 to clear the loan, then find the time period of the loan.

(9) Daniel took a loan of $6200 at the rate of 10% simple interest per annum. If he paid an amount of $11160 to clear the loan, then find the time period of the loan.

(10) Find the amount to be paid if William borrowed a sum of $5500 at 9% simple interest for 8 years.