Simple Interest
Math MCQs

Question :  ( 1 of 10 )  What amount does Richard have to pay after 6 years if he takes a loan of $3600 at 5% simple interest?

Correct Answer  $4680

Solution & Explanation

Solution

Given,

Principal (P) = $3600

Rate of Simple Interest (SI) = 5%

Time (t) = 6 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) = $3600 × 5% × 6

= $3600 ×⁵/₁₀₀ × 6

= ^{3600 × 5 × 6}/₁₀₀

= ^{18000 × 6}/₁₀₀

= ¹⁰⁸⁰⁰⁰/₁₀₀

= $1080

Thus, Simple Interest = $1080

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 = $3600 + $1080

= $4680

Thus, Amount to be paid = $4680 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 = $3600

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

And, Time (t) = 6 years

Thus, Amount (A)

= $3600 + ($3600 × 5% × 6)

= $3600 + ($3600 ×⁵/₁₀₀ × 6)

= $3600 + (^{3600 × 5 × 6}/₁₀₀)

= $3600 + (^{18000 × 6}/₁₀₀)

= $3600 + (¹⁰⁸⁰⁰⁰/₁₀₀)

= $3600 + $1080 = $4680

Thus, Amount (A) to be paid = $4680 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 $3600, the simple interest in 1 year

= ⁵/₁₀₀ × 3600

= ^{5 × 3600}/₁₀₀

= ¹⁸⁰⁰⁰/₁₀₀ = $180

Thus, simple interest for 1 year = $180

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $180 × 6 = $1080

Thus, Simple Interest (SI) = $1080

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3600 + $1080

= $4680

Thus, Amount to be paid = $4680 Answer

Similar Questions

(1) What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 5% simple interest?

(2) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 9% simple interest for 7 years.

(3) Calculate the amount due if Barbara borrowed a sum of $3550 at 10% simple interest for 3 years.

(4) Robert took a loan of $4200 at the rate of 6% simple interest per annum. If he paid an amount of $6468 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due after 10 years if Charles borrowed a sum of $5900 at a rate of 2% simple interest.

(6) Find the amount to be paid if James borrowed a sum of $5000 at 3% simple interest for 8 years.

(7) Michelle had to pay $5692.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(8) What amount will be due after 2 years if Thomas borrowed a sum of $3400 at a 4% simple interest?

(9) What amount does Michael have to pay after 5 years if he takes a loan of $3300 at 4% simple interest?

(10) What amount does David have to pay after 6 years if he takes a loan of $3400 at 10% simple interest?