Simple Interest
Math MCQs

Question :    What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 9% simple interest?

Correct Answer  $3894

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 9%

Time (t) = 2 years

Thus, Amount (A) = ?

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

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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) = $3300 × 9% × 2

= $3300 ×⁹/₁₀₀ × 2

= ^{3300 × 9 × 2}/₁₀₀

= ^{29700 × 2}/₁₀₀

= ⁵⁹⁴⁰⁰/₁₀₀

= $594

Thus, Simple Interest = $594

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 = $3300 + $594

= $3894

Thus, Amount to be paid = $3894 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 = $3300

Rate of Simple Interest (SI) or (R) = 9%

And, Time (t) = 2 years

Thus, Amount (A)

= $3300 + ($3300 × 9% × 2)

= $3300 + ($3300 ×⁹/₁₀₀ × 2)

= $3300 + (^{3300 × 9 × 2}/₁₀₀)

= $3300 + (^{29700 × 2}/₁₀₀)

= $3300 + (⁵⁹⁴⁰⁰/₁₀₀)

= $3300 + $594 = $3894

Thus, Amount (A) to be paid = $3894 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = ⁹/₁₀₀

∴ For $3300, the simple interest in 1 year

= ⁹/₁₀₀ × 3300

= ^{9 × 3300}/₁₀₀

= ²⁹⁷⁰⁰/₁₀₀ = $297

Thus, simple interest for 1 year = $297

Therefore, simple interest for 2 years

= Simple interest for 1 year × 2

= $297 × 2 = $594

Thus, Simple Interest (SI) = $594

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $594

= $3894

Thus, Amount to be paid = $3894 Answer

Similar Questions

(1) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 4% simple interest for 8 years.

(2) Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 6% simple interest.

(3) Sandra took a loan of $6900 at the rate of 6% simple interest per annum. If he paid an amount of $9798 to clear the loan, then find the time period of the loan.

(4) Michael had to pay $3795 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(5) What amount does Sarah have to pay after 6 years if he takes a loan of $3850 at 7% simple interest?

(6) Find the amount to be paid if Patricia borrowed a sum of $5150 at 5% simple interest for 8 years.

(7) How much loan did Ryan borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $9085 to clear it?

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

(9) Lisa took a loan of $6100 at the rate of 7% simple interest per annum. If he paid an amount of $8662 to clear the loan, then find the time period of the loan.

(10) John took a loan of $4400 at the rate of 9% simple interest per annum. If he paid an amount of $7568 to clear the loan, then find the time period of the loan.