Simple Interest
Math MCQs

Question :    Calculate the amount due if Michael borrowed a sum of $3300 at 3% simple interest for 3 years.

Correct Answer  $3597

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 3%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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 × 3% × 3

= $3300 ׳/₁₀₀ × 3

= ^{3300 × 3 × 3}/₁₀₀

= ^{9900 × 3}/₁₀₀

= ²⁹⁷⁰⁰/₁₀₀

= $297

Thus, Simple Interest = $297

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 + $297

= $3597

Thus, Amount to be paid = $3597 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) = 3%

And, Time (t) = 3 years

Thus, Amount (A)

= $3300 + ($3300 × 3% × 3)

= $3300 + ($3300 ׳/₁₀₀ × 3)

= $3300 + (^{3300 × 3 × 3}/₁₀₀)

= $3300 + (^{9900 × 3}/₁₀₀)

= $3300 + (²⁹⁷⁰⁰/₁₀₀)

= $3300 + $297 = $3597

Thus, Amount (A) to be paid = $3597 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = ³/₁₀₀

∴ For $3300, the simple interest in 1 year

= ³/₁₀₀ × 3300

= ^{3 × 3300}/₁₀₀

= ⁹⁹⁰⁰/₁₀₀ = $99

Thus, simple interest for 1 year = $99

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $99 × 3 = $297

Thus, Simple Interest (SI) = $297

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $297

= $3597

Thus, Amount to be paid = $3597 Answer

Similar Questions

(1) Sarah had to pay $4081 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(2) Calculate the amount due if Robert borrowed a sum of $3100 at 7% simple interest for 3 years.

(3) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 4% simple interest?

(4) Charles took a loan of $5800 at the rate of 7% simple interest per annum. If he paid an amount of $9048 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 6% simple interest.

(6) Matthew took a loan of $6400 at the rate of 6% simple interest per annum. If he paid an amount of $8704 to clear the loan, then find the time period of the loan.

(7) William had to pay $4025 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(8) Charles had to pay $4485 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(9) Calculate the amount due if Karen borrowed a sum of $3950 at 2% simple interest for 3 years.

(10) Calculate the amount due if Linda borrowed a sum of $3350 at 6% simple interest for 3 years.