Simple Interest
Math MCQs

Question :    Calculate the amount due if Richard borrowed a sum of $3600 at 6% simple interest for 3 years.

Correct Answer  $4248

Solution & Explanation

Solution

Given,

Principal (P) = $3600

Rate of Simple Interest (SI) = 6%

Time (t) = 3 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% × 3

= $3600 ×⁶/₁₀₀ × 3

= ^{3600 × 6 × 3}/₁₀₀

= ^{21600 × 3}/₁₀₀

= ⁶⁴⁸⁰⁰/₁₀₀

= $648

Thus, Simple Interest = $648

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 + $648

= $4248

Thus, Amount to be paid = $4248 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) = 3 years

Thus, Amount (A)

= $3600 + ($3600 × 6% × 3)

= $3600 + ($3600 ×⁶/₁₀₀ × 3)

= $3600 + (^{3600 × 6 × 3}/₁₀₀)

= $3600 + (^{21600 × 3}/₁₀₀)

= $3600 + (⁶⁴⁸⁰⁰/₁₀₀)

= $3600 + $648 = $4248

Thus, Amount (A) to be paid = $4248 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 3 years

= Simple interest for 1 year × 3

= $216 × 3 = $648

Thus, Simple Interest (SI) = $648

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3600 + $648

= $4248

Thus, Amount to be paid = $4248 Answer

Similar Questions

(1) What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 4% simple interest?

(2) In how much time a principal of $3050 will amount to $3660 at a simple interest of 5% per annum?

(3) Calculate the amount due if John borrowed a sum of $3200 at 3% simple interest for 3 years.

(4) How much loan did Joseph borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6555 to clear it?

(5) Sarah took a loan of $5700 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.

(6) Find the amount to be paid if Karen borrowed a sum of $5950 at 8% simple interest for 7 years.

(7) John took a loan of $4400 at the rate of 9% simple interest per annum. If he paid an amount of $8360 to clear the loan, then find the time period of the loan.

(8) Joseph took a loan of $5400 at the rate of 9% simple interest per annum. If he paid an amount of $9774 to clear the loan, then find the time period of the loan.

(9) Jessica took a loan of $5500 at the rate of 7% simple interest per annum. If he paid an amount of $8195 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 8% simple interest.