Simple Interest
Math MCQs

Question :    Find the amount to be paid if Charles borrowed a sum of $5900 at 3% simple interest for 7 years.

Correct Answer  $7139

Solution & Explanation

Solution

Given,

Principal (P) = $5900

Rate of Simple Interest (SI) = 3%

Time (t) = 7 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) = $5900 × 3% × 7

= $5900 ׳/₁₀₀ × 7

= ^{5900 × 3 × 7}/₁₀₀

= ^{17700 × 7}/₁₀₀

= ¹²³⁹⁰⁰/₁₀₀

= $1239

Thus, Simple Interest = $1239

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 = $5900 + $1239

= $7139

Thus, Amount to be paid = $7139 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 = $5900

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

And, Time (t) = 7 years

Thus, Amount (A)

= $5900 + ($5900 × 3% × 7)

= $5900 + ($5900 ׳/₁₀₀ × 7)

= $5900 + (^{5900 × 3 × 7}/₁₀₀)

= $5900 + (^{17700 × 7}/₁₀₀)

= $5900 + (¹²³⁹⁰⁰/₁₀₀)

= $5900 + $1239 = $7139

Thus, Amount (A) to be paid = $7139 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 $5900, the simple interest in 1 year

= ³/₁₀₀ × 5900

= ^{3 × 5900}/₁₀₀

= ¹⁷⁷⁰⁰/₁₀₀ = $177

Thus, simple interest for 1 year = $177

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $177 × 7 = $1239

Thus, Simple Interest (SI) = $1239

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5900 + $1239

= $7139

Thus, Amount to be paid = $7139 Answer

Similar Questions

(1) Betty took a loan of $6500 at the rate of 9% simple interest per annum. If he paid an amount of $10595 to clear the loan, then find the time period of the loan.

(2) David took a loan of $4800 at the rate of 8% simple interest per annum. If he paid an amount of $7872 to clear the loan, then find the time period of the loan.

(3) How much loan did Stephanie borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8305 to clear it?

(4) Joseph took a loan of $5400 at the rate of 10% simple interest per annum. If he paid an amount of $8640 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due if Linda borrowed a sum of $3350 at 10% simple interest for 4 years.

(6) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 6% simple interest.

(7) Patricia took a loan of $4300 at the rate of 7% simple interest per annum. If he paid an amount of $7310 to clear the loan, then find the time period of the loan.

(8) What amount will be due after 2 years if William borrowed a sum of $3250 at a 4% simple interest?

(9) Find the amount to be paid if James borrowed a sum of $5000 at 8% simple interest for 7 years.

(10) What amount does Jennifer have to pay after 6 years if he takes a loan of $3250 at 5% simple interest?