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) How much loan did Amanda borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8937.5 to clear it?

(2) Find the amount to be paid if James borrowed a sum of $5000 at 4% simple interest for 8 years.

(3) Michael took a loan of $4600 at the rate of 7% simple interest per annum. If he paid an amount of $7176 to clear the loan, then find the time period of the loan.

(4) Matthew took a loan of $6400 at the rate of 6% simple interest per annum. If he paid an amount of $9088 to clear the loan, then find the time period of the loan.

(5) What amount does Michael have to pay after 6 years if he takes a loan of $3300 at 3% simple interest?

(6) Find the amount to be paid if Robert borrowed a sum of $5100 at 6% simple interest for 8 years.

(7) What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 7% simple interest?

(8) Jennifer took a loan of $4500 at the rate of 10% simple interest per annum. If he paid an amount of $8100 to clear the loan, then find the time period of the loan.

(9) Donald took a loan of $7000 at the rate of 6% simple interest per annum. If he paid an amount of $9520 to clear the loan, then find the time period of the loan.

(10) Christopher took a loan of $6000 at the rate of 8% simple interest per annum. If he paid an amount of $10800 to clear the loan, then find the time period of the loan.