Simple Interest
Math MCQs

Question :    Calculate the amount due if James borrowed a sum of $3000 at 3% simple interest for 3 years.

Correct Answer  $3270

Solution & Explanation

Solution

Given,

Principal (P) = $3000

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) = $3000 × 3% × 3

= $3000 ׳/₁₀₀ × 3

= ^{3000 × 3 × 3}/₁₀₀

= ^{9000 × 3}/₁₀₀

= ²⁷⁰⁰⁰/₁₀₀

= $270

Thus, Simple Interest = $270

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 = $3000 + $270

= $3270

Thus, Amount to be paid = $3270 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 = $3000

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 3 years

Thus, Amount (A)

= $3000 + ($3000 × 3% × 3)

= $3000 + ($3000 ׳/₁₀₀ × 3)

= $3000 + (^{3000 × 3 × 3}/₁₀₀)

= $3000 + (^{9000 × 3}/₁₀₀)

= $3000 + (²⁷⁰⁰⁰/₁₀₀)

= $3000 + $270 = $3270

Thus, Amount (A) to be paid = $3270 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 $3000, the simple interest in 1 year

= ³/₁₀₀ × 3000

= ^{3 × 3000}/₁₀₀

= ⁹⁰⁰⁰/₁₀₀ = $90

Thus, simple interest for 1 year = $90

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $90 × 3 = $270

Thus, Simple Interest (SI) = $270

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3000 + $270

= $3270

Thus, Amount to be paid = $3270 Answer

Similar Questions

(1) Matthew had to pay $4578 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(2) Calculate the amount due if Jessica borrowed a sum of $3750 at 4% simple interest for 3 years.

(3) Calculate the amount due after 10 years if Christopher borrowed a sum of $6000 at a rate of 8% simple interest.

(4) What amount does John have to pay after 6 years if he takes a loan of $3200 at 2% simple interest?

(5) Jessica took a loan of $5500 at the rate of 8% simple interest per annum. If he paid an amount of $8580 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 6% simple interest for 4 years.

(7) Joseph took a loan of $5400 at the rate of 8% simple interest per annum. If he paid an amount of $9288 to clear the loan, then find the time period of the loan.

(8) How much loan did Ashley borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7860 to clear it?

(9) What amount does Charles have to pay after 6 years if he takes a loan of $3900 at 6% simple interest?

(10) Mary took a loan of $4100 at the rate of 9% simple interest per annum. If he paid an amount of $6683 to clear the loan, then find the time period of the loan.