Simple Interest
Math MCQs

Question :    Calculate the amount due if Richard borrowed a sum of $3600 at 6% simple interest for 4 years.

Correct Answer  $4464

Solution & Explanation

Solution

Given,

Principal (P) = $3600

Rate of Simple Interest (SI) = 6%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $3600 × 6% × 4

= $3600 ×⁶/₁₀₀ × 4

= ^{3600 × 6 × 4}/₁₀₀

= ^{21600 × 4}/₁₀₀

= ⁸⁶⁴⁰⁰/₁₀₀

= $864

Thus, Simple Interest = $864

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 = $3600 + $864

= $4464

Thus, Amount to be paid = $4464 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 = $3600

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 4 years

Thus, Amount (A)

= $3600 + ($3600 × 6% × 4)

= $3600 + ($3600 ×⁶/₁₀₀ × 4)

= $3600 + (^{3600 × 6 × 4}/₁₀₀)

= $3600 + (^{21600 × 4}/₁₀₀)

= $3600 + (⁸⁶⁴⁰⁰/₁₀₀)

= $3600 + $864 = $4464

Thus, Amount (A) to be paid = $4464 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $3600, the simple interest in 1 year

= ⁶/₁₀₀ × 3600

= ^{6 × 3600}/₁₀₀

= ²¹⁶⁰⁰/₁₀₀ = $216

Thus, simple interest for 1 year = $216

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $216 × 4 = $864

Thus, Simple Interest (SI) = $864

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3600 + $864

= $4464

Thus, Amount to be paid = $4464 Answer

Similar Questions

(1) Betty took a loan of $6500 at the rate of 7% simple interest per annum. If he paid an amount of $9685 to clear the loan, then find the time period of the loan.

(2) Sandra took a loan of $6900 at the rate of 7% simple interest per annum. If he paid an amount of $10281 to clear the loan, then find the time period of the loan.

(3) Mark took a loan of $6800 at the rate of 9% simple interest per annum. If he paid an amount of $11084 to clear the loan, then find the time period of the loan.

(4) If William borrowed $3500 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(5) Matthew had to pay $4452 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(6) Calculate the amount due after 9 years if Barbara borrowed a sum of $5550 at a rate of 2% simple interest.

(7) Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 4% simple interest.

(8) If William borrowed $3500 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(9) Calculate the amount due if Sarah borrowed a sum of $3850 at 8% simple interest for 4 years.

(10) If Donald paid $5400 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.