Simple Interest
Math MCQs

Question :  ( 1 of 10 )  What amount does John have to pay after 6 years if he takes a loan of $3200 at 4% simple interest?

Correct Answer  $3968

Solution & Explanation

Solution

Given,

Principal (P) = $3200

Rate of Simple Interest (SI) = 4%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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 × 4% × 6

= $3200 ×⁴/₁₀₀ × 6

= ^{3200 × 4 × 6}/₁₀₀

= ^{12800 × 6}/₁₀₀

= ⁷⁶⁸⁰⁰/₁₀₀

= $768

Thus, Simple Interest = $768

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 + $768

= $3968

Thus, Amount to be paid = $3968 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) = 4%

And, Time (t) = 6 years

Thus, Amount (A)

= $3200 + ($3200 × 4% × 6)

= $3200 + ($3200 ×⁴/₁₀₀ × 6)

= $3200 + (^{3200 × 4 × 6}/₁₀₀)

= $3200 + (^{12800 × 6}/₁₀₀)

= $3200 + (⁷⁶⁸⁰⁰/₁₀₀)

= $3200 + $768 = $3968

Thus, Amount (A) to be paid = $3968 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $3200, the simple interest in 1 year

= ⁴/₁₀₀ × 3200

= ^{4 × 3200}/₁₀₀

= ¹²⁸⁰⁰/₁₀₀ = $128

Thus, simple interest for 1 year = $128

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $128 × 6 = $768

Thus, Simple Interest (SI) = $768

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3200 + $768

= $3968

Thus, Amount to be paid = $3968 Answer

Similar Questions

(1) Calculate the amount due if Patricia borrowed a sum of $3150 at 8% simple interest for 4 years.

(2) Elizabeth had to pay $3657 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(3) Sarah took a loan of $5700 at the rate of 6% simple interest per annum. If he paid an amount of $8436 to clear the loan, then find the time period of the loan.

(4) Find the amount to be paid if Linda borrowed a sum of $5350 at 8% simple interest for 8 years.

(5) William took a loan of $5000 at the rate of 6% simple interest per annum. If he paid an amount of $7400 to clear the loan, then find the time period of the loan.

(6) Michael took a loan of $4600 at the rate of 10% simple interest per annum. If he paid an amount of $8280 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due if Karen borrowed a sum of $3950 at 8% simple interest for 4 years.

(8) What amount does Jennifer have to pay after 5 years if he takes a loan of $3250 at 7% simple interest?

(9) What amount does Linda have to pay after 6 years if he takes a loan of $3350 at 8% simple interest?

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