Simple Interest
Math MCQs

Question :    Find the amount to be paid if Christopher borrowed a sum of $6000 at 2% simple interest for 8 years.

Correct Answer  $6960

Solution & Explanation

Solution

Given,

Principal (P) = $6000

Rate of Simple Interest (SI) = 2%

Time (t) = 8 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) = $6000 × 2% × 8

= $6000 ײ/₁₀₀ × 8

= ^{6000 × 2 × 8}/₁₀₀

= ^{12000 × 8}/₁₀₀

= ⁹⁶⁰⁰⁰/₁₀₀

= $960

Thus, Simple Interest = $960

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 = $6000 + $960

= $6960

Thus, Amount to be paid = $6960 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 = $6000

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

And, Time (t) = 8 years

Thus, Amount (A)

= $6000 + ($6000 × 2% × 8)

= $6000 + ($6000 ײ/₁₀₀ × 8)

= $6000 + (^{6000 × 2 × 8}/₁₀₀)

= $6000 + (^{12000 × 8}/₁₀₀)

= $6000 + (⁹⁶⁰⁰⁰/₁₀₀)

= $6000 + $960 = $6960

Thus, Amount (A) to be paid = $6960 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 $6000, the simple interest in 1 year

= ²/₁₀₀ × 6000

= ^{2 × 6000}/₁₀₀

= ¹²⁰⁰⁰/₁₀₀ = $120

Thus, simple interest for 1 year = $120

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $120 × 8 = $960

Thus, Simple Interest (SI) = $960

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $6000 + $960

= $6960

Thus, Amount to be paid = $6960 Answer

Similar Questions

(1) Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 10% simple interest.

(2) Calculate the amount due after 9 years if James borrowed a sum of $5000 at a rate of 7% simple interest.

(3) Calculate the amount due if Richard borrowed a sum of $3600 at 5% simple interest for 3 years.

(4) What amount does David have to pay after 5 years if he takes a loan of $3400 at 9% simple interest?

(5) What amount does Richard have to pay after 6 years if he takes a loan of $3600 at 5% simple interest?

(6) Richard had to pay $3924 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(7) Find the amount to be paid if Richard borrowed a sum of $5600 at 7% simple interest for 8 years.

(8) How much loan did Jennifer borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $6300 to clear it?

(9) David took a loan of $4800 at the rate of 6% simple interest per annum. If he paid an amount of $6816 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 8% simple interest.