Simple Interest
Math MCQs

Question :    Calculate the amount due if Barbara borrowed a sum of $3550 at 8% simple interest for 3 years.

Correct Answer  $4402

Solution & Explanation

Solution

Given,

Principal (P) = $3550

Rate of Simple Interest (SI) = 8%

Time (t) = 3 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) = $3550 × 8% × 3

= $3550 ×⁸/₁₀₀ × 3

= ^{3550 × 8 × 3}/₁₀₀

= ^{28400 × 3}/₁₀₀

= ⁸⁵²⁰⁰/₁₀₀

= $852

Thus, Simple Interest = $852

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 = $3550 + $852

= $4402

Thus, Amount to be paid = $4402 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 = $3550

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

And, Time (t) = 3 years

Thus, Amount (A)

= $3550 + ($3550 × 8% × 3)

= $3550 + ($3550 ×⁸/₁₀₀ × 3)

= $3550 + (^{3550 × 8 × 3}/₁₀₀)

= $3550 + (^{28400 × 3}/₁₀₀)

= $3550 + (⁸⁵²⁰⁰/₁₀₀)

= $3550 + $852 = $4402

Thus, Amount (A) to be paid = $4402 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 $3550, the simple interest in 1 year

= ⁸/₁₀₀ × 3550

= ^{8 × 3550}/₁₀₀

= ²⁸⁴⁰⁰/₁₀₀ = $284

Thus, simple interest for 1 year = $284

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $284 × 3 = $852

Thus, Simple Interest (SI) = $852

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3550 + $852

= $4402

Thus, Amount to be paid = $4402 Answer

Similar Questions

(1) What amount does Christopher have to pay after 5 years if he takes a loan of $4000 at 2% simple interest?

(2) What amount does Richard have to pay after 5 years if he takes a loan of $3600 at 9% simple interest?

(3) Calculate the amount due if Jennifer borrowed a sum of $3250 at 3% simple interest for 4 years.

(4) Mark had to pay $5060 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(5) Sandra took a loan of $6900 at the rate of 9% simple interest per annum. If he paid an amount of $13110 to clear the loan, then find the time period of the loan.

(6) If Steven paid $5152 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(7) In how much time a principal of $3050 will amount to $3538 at a simple interest of 4% per annum?

(8) Mark took a loan of $6800 at the rate of 6% simple interest per annum. If he paid an amount of $9656 to clear the loan, then find the time period of the loan.

(9) If Lisa paid $4536 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(10) What amount will be due after 2 years if David borrowed a sum of $3200 at a 6% simple interest?