Simple Interest
Math MCQs

Question :    Calculate the amount due if Michael borrowed a sum of $3300 at 9% simple interest for 4 years.

Correct Answer  $4488

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 9%

Time (t) = 4 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% × 4

= $3300 ×⁹/₁₀₀ × 4

= ^{3300 × 9 × 4}/₁₀₀

= ^{29700 × 4}/₁₀₀

= ¹¹⁸⁸⁰⁰/₁₀₀

= $1188

Thus, Simple Interest = $1188

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 + $1188

= $4488

Thus, Amount to be paid = $4488 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) = 4 years

Thus, Amount (A)

= $3300 + ($3300 × 9% × 4)

= $3300 + ($3300 ×⁹/₁₀₀ × 4)

= $3300 + (^{3300 × 9 × 4}/₁₀₀)

= $3300 + (^{29700 × 4}/₁₀₀)

= $3300 + (¹¹⁸⁸⁰⁰/₁₀₀)

= $3300 + $1188 = $4488

Thus, Amount (A) to be paid = $4488 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 4 years

= Simple interest for 1 year × 4

= $297 × 4 = $1188

Thus, Simple Interest (SI) = $1188

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $1188

= $4488

Thus, Amount to be paid = $4488 Answer

Similar Questions

(1) Calculate the amount due if Mary borrowed a sum of $3050 at 2% simple interest for 3 years.

(2) William took a loan of $5000 at the rate of 9% simple interest per annum. If he paid an amount of $8600 to clear the loan, then find the time period of the loan.

(3) Jennifer took a loan of $4500 at the rate of 6% simple interest per annum. If he paid an amount of $6930 to clear the loan, then find the time period of the loan.

(4) Find the amount to be paid if Mary borrowed a sum of $5050 at 7% simple interest for 8 years.

(5) Find the amount to be paid if Susan borrowed a sum of $5650 at 5% simple interest for 8 years.

(6) Lisa had to pay $4657.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(7) What amount does Jennifer have to pay after 6 years if he takes a loan of $3250 at 7% simple interest?

(8) Calculate the amount due if John borrowed a sum of $3200 at 3% simple interest for 3 years.

(9) How much loan did Kimberly borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $7315 to clear it?

(10) If Anthony paid $4644 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.