Simple Interest
Math MCQs

Question :    Find the amount to be paid if Susan borrowed a sum of $5650 at 2% simple interest for 7 years.

Correct Answer  $6441

Solution & Explanation

Solution

Given,

Principal (P) = $5650

Rate of Simple Interest (SI) = 2%

Time (t) = 7 years

Thus, Amount (A) = ?

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

Thus, here 2% simple interest means, Rate of Simple Interest (SI) is 2% 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) = $5650 × 2% × 7

= $5650 ײ/₁₀₀ × 7

= ^{5650 × 2 × 7}/₁₀₀

= ^{11300 × 7}/₁₀₀

= ⁷⁹¹⁰⁰/₁₀₀

= $791

Thus, Simple Interest = $791

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 = $5650 + $791

= $6441

Thus, Amount to be paid = $6441 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 = $5650

Rate of Simple Interest (SI) or (R) = 2%

And, Time (t) = 7 years

Thus, Amount (A)

= $5650 + ($5650 × 2% × 7)

= $5650 + ($5650 ײ/₁₀₀ × 7)

= $5650 + (^{5650 × 2 × 7}/₁₀₀)

= $5650 + (^{11300 × 7}/₁₀₀)

= $5650 + (⁷⁹¹⁰⁰/₁₀₀)

= $5650 + $791 = $6441

Thus, Amount (A) to be paid = $6441 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 2%

This, means, $2 per $100 per year

∵ For $100, the simple interest for 1 year = $2

∴ For $1, the simple interest for 1 year = ²/₁₀₀

∴ For $5650, the simple interest in 1 year

= ²/₁₀₀ × 5650

= ^{2 × 5650}/₁₀₀

= ¹¹³⁰⁰/₁₀₀ = $113

Thus, simple interest for 1 year = $113

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $113 × 7 = $791

Thus, Simple Interest (SI) = $791

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5650 + $791

= $6441

Thus, Amount to be paid = $6441 Answer

Similar Questions

(1) Jessica had to pay $4200 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(2) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $6846 to clear the loan, then find the time period of the loan.

(3) What amount will be due after 2 years if Charles borrowed a sum of $3450 at a 9% simple interest?

(4) Find the amount to be paid if Thomas borrowed a sum of $5800 at 5% simple interest for 8 years.

(5) 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.

(6) What amount does Jennifer have to pay after 6 years if he takes a loan of $3250 at 3% simple interest?

(7) If Andrew paid $5760 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(8) What amount does Jessica have to pay after 6 years if he takes a loan of $3750 at 5% simple interest?

(9) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 10% simple interest for 4 years.

(10) Calculate the amount due if Robert borrowed a sum of $3100 at 8% simple interest for 3 years.