Simple Interest
Math MCQs

Question :    Calculate the amount due if Joseph borrowed a sum of $3700 at 8% simple interest for 3 years.

Correct Answer  $4588

Solution & Explanation

Solution

Given,

Principal (P) = $3700

Rate of Simple Interest (SI) = 8%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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) = $3700 × 8% × 3

= $3700 ×⁸/₁₀₀ × 3

= ^{3700 × 8 × 3}/₁₀₀

= ^{29600 × 3}/₁₀₀

= ⁸⁸⁸⁰⁰/₁₀₀

= $888

Thus, Simple Interest = $888

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 = $3700 + $888

= $4588

Thus, Amount to be paid = $4588 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 = $3700

Rate of Simple Interest (SI) or (R) = 8%

And, Time (t) = 3 years

Thus, Amount (A)

= $3700 + ($3700 × 8% × 3)

= $3700 + ($3700 ×⁸/₁₀₀ × 3)

= $3700 + (^{3700 × 8 × 3}/₁₀₀)

= $3700 + (^{29600 × 3}/₁₀₀)

= $3700 + (⁸⁸⁸⁰⁰/₁₀₀)

= $3700 + $888 = $4588

Thus, Amount (A) to be paid = $4588 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = ⁸/₁₀₀

∴ For $3700, the simple interest in 1 year

= ⁸/₁₀₀ × 3700

= ^{8 × 3700}/₁₀₀

= ²⁹⁶⁰⁰/₁₀₀ = $296

Thus, simple interest for 1 year = $296

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $296 × 3 = $888

Thus, Simple Interest (SI) = $888

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3700 + $888

= $4588

Thus, Amount to be paid = $4588 Answer

Similar Questions

(1) Charles took a loan of $5800 at the rate of 9% simple interest per annum. If he paid an amount of $9454 to clear the loan, then find the time period of the loan.

(2) Find the amount to be paid if Barbara borrowed a sum of $5550 at 10% simple interest for 8 years.

(3) Elizabeth took a loan of $4900 at the rate of 7% simple interest per annum. If he paid an amount of $6958 to clear the loan, then find the time period of the loan.

(4) How much loan did Margaret borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7302.5 to clear it?

(5) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 8% simple interest.

(6) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 3% simple interest.

(7) David took a loan of $4800 at the rate of 10% simple interest per annum. If he paid an amount of $9120 to clear the loan, then find the time period of the loan.

(8) John had to pay $3680 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 after 9 years if Charles borrowed a sum of $5900 at a rate of 5% simple interest.

(10) Christopher took a loan of $6000 at the rate of 10% simple interest per annum. If he paid an amount of $9600 to clear the loan, then find the time period of the loan.