Simple Interest
Math MCQs

Question :    Calculate the amount due if Joseph borrowed a sum of $3700 at 4% simple interest for 3 years.

Correct Answer  $4144

Solution & Explanation

Solution

Given,

Principal (P) = $3700

Rate of Simple Interest (SI) = 4%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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 × 4% × 3

= $3700 ×⁴/₁₀₀ × 3

= ^{3700 × 4 × 3}/₁₀₀

= ^{14800 × 3}/₁₀₀

= ⁴⁴⁴⁰⁰/₁₀₀

= $444

Thus, Simple Interest = $444

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 + $444

= $4144

Thus, Amount to be paid = $4144 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) = 4%

And, Time (t) = 3 years

Thus, Amount (A)

= $3700 + ($3700 × 4% × 3)

= $3700 + ($3700 ×⁴/₁₀₀ × 3)

= $3700 + (^{3700 × 4 × 3}/₁₀₀)

= $3700 + (^{14800 × 3}/₁₀₀)

= $3700 + (⁴⁴⁴⁰⁰/₁₀₀)

= $3700 + $444 = $4144

Thus, Amount (A) to be paid = $4144 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $3700, the simple interest in 1 year

= ⁴/₁₀₀ × 3700

= ^{4 × 3700}/₁₀₀

= ¹⁴⁸⁰⁰/₁₀₀ = $148

Thus, simple interest for 1 year = $148

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $148 × 3 = $444

Thus, Simple Interest (SI) = $444

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3700 + $444

= $4144

Thus, Amount to be paid = $4144 Answer

Similar Questions

(1) Calculate the amount due after 10 years if Robert borrowed a sum of $5100 at a rate of 6% simple interest.

(2) Michael took a loan of $4600 at the rate of 10% simple interest per annum. If he paid an amount of $8740 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due after 10 years if Robert borrowed a sum of $5100 at a rate of 2% simple interest.

(4) William took a loan of $5000 at the rate of 7% simple interest per annum. If he paid an amount of $7800 to clear the loan, then find the time period of the loan.

(5) Jessica took a loan of $5500 at the rate of 10% simple interest per annum. If he paid an amount of $10450 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 10% simple interest.

(7) If Jessica paid $4200 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(8) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 3% simple interest.

(9) What amount does Sarah have to pay after 6 years if he takes a loan of $3850 at 6% simple interest?

(10) Calculate the amount due after 10 years if William borrowed a sum of $5500 at a rate of 8% simple interest.