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) Find the amount to be paid if Michael borrowed a sum of $5300 at 7% simple interest for 8 years.

(2) Calculate the amount due after 9 years if David borrowed a sum of $5400 at a rate of 6% simple interest.

(3) Margaret took a loan of $6700 at the rate of 8% simple interest per annum. If he paid an amount of $10988 to clear the loan, then find the time period of the loan.

(4) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $10269 to clear the loan, then find the time period of the loan.

(5) How much loan did Linda borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $6420 to clear it?

(6) Donald took a loan of $7000 at the rate of 8% simple interest per annum. If he paid an amount of $11480 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due if James borrowed a sum of $3000 at 8% simple interest for 3 years.

(8) Calculate the amount due after 9 years if Elizabeth borrowed a sum of $5450 at a rate of 2% simple interest.

(9) David took a loan of $4800 at the rate of 8% simple interest per annum. If he paid an amount of $8256 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 7% simple interest.