Simple Interest
Math MCQs

Question :    What amount does John have to pay after 6 years if he takes a loan of $3200 at 8% simple interest?

Correct Answer  $4736

Solution & Explanation

Solution

Given,

Principal (P) = $3200

Rate of Simple Interest (SI) = 8%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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) = $3200 × 8% × 6

= $3200 ×⁸/₁₀₀ × 6

= ^{3200 × 8 × 6}/₁₀₀

= ^{25600 × 6}/₁₀₀

= ¹⁵³⁶⁰⁰/₁₀₀

= $1536

Thus, Simple Interest = $1536

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 = $3200 + $1536

= $4736

Thus, Amount to be paid = $4736 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 = $3200

Rate of Simple Interest (SI) or (R) = 8%

And, Time (t) = 6 years

Thus, Amount (A)

= $3200 + ($3200 × 8% × 6)

= $3200 + ($3200 ×⁸/₁₀₀ × 6)

= $3200 + (^{3200 × 8 × 6}/₁₀₀)

= $3200 + (^{25600 × 6}/₁₀₀)

= $3200 + (¹⁵³⁶⁰⁰/₁₀₀)

= $3200 + $1536 = $4736

Thus, Amount (A) to be paid = $4736 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = ⁸/₁₀₀

∴ For $3200, the simple interest in 1 year

= ⁸/₁₀₀ × 3200

= ^{8 × 3200}/₁₀₀

= ²⁵⁶⁰⁰/₁₀₀ = $256

Thus, simple interest for 1 year = $256

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $256 × 6 = $1536

Thus, Simple Interest (SI) = $1536

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3200 + $1536

= $4736

Thus, Amount to be paid = $4736 Answer

Similar Questions

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

(2) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 2% simple interest.

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

(4) What amount does John have to pay after 6 years if he takes a loan of $3200 at 8% simple interest?

(5) Margaret took a loan of $6700 at the rate of 10% simple interest per annum. If he paid an amount of $12730 to clear the loan, then find the time period of the loan.

(6) How much loan did Matthew borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6820 to clear it?

(7) What amount does David have to pay after 6 years if he takes a loan of $3400 at 9% simple interest?

(8) Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 7% simple interest.

(9) What amount does Thomas have to pay after 6 years if he takes a loan of $3800 at 9% simple interest?

(10) Find the amount to be paid if James borrowed a sum of $5000 at 10% simple interest for 8 years.