Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if David borrowed a sum of $5400 at a rate of 3% simple interest.

Correct Answer  $7020

Solution & Explanation

Solution

Given,

Principal (P) = $5400

Rate of Simple Interest (SI) = 3%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $5400 × 3% × 10

= $5400 ׳/₁₀₀ × 10

= ^{5400 × 3 × 10}/₁₀₀

= ^{16200 × 10}/₁₀₀

= ¹⁶²⁰⁰⁰/₁₀₀

= $1620

Thus, Simple Interest = $1620

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 = $5400 + $1620

= $7020

Thus, Amount to be paid = $7020 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 = $5400

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 10 years

Thus, Amount (A)

= $5400 + ($5400 × 3% × 10)

= $5400 + ($5400 ׳/₁₀₀ × 10)

= $5400 + (^{5400 × 3 × 10}/₁₀₀)

= $5400 + (^{16200 × 10}/₁₀₀)

= $5400 + (¹⁶²⁰⁰⁰/₁₀₀)

= $5400 + $1620 = $7020

Thus, Amount (A) to be paid = $7020 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = ³/₁₀₀

∴ For $5400, the simple interest in 1 year

= ³/₁₀₀ × 5400

= ^{3 × 5400}/₁₀₀

= ¹⁶²⁰⁰/₁₀₀ = $162

Thus, simple interest for 1 year = $162

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $162 × 10 = $1620

Thus, Simple Interest (SI) = $1620

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5400 + $1620

= $7020

Thus, Amount to be paid = $7020 Answer

Similar Questions

(1) Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 2% simple interest.

(2) Christopher took a loan of $6000 at the rate of 9% simple interest per annum. If he paid an amount of $9780 to clear the loan, then find the time period of the loan.

(3) Michael had to pay $3795 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(4) Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 8% simple interest.

(5) What amount does Michael have to pay after 5 years if he takes a loan of $3300 at 6% simple interest?

(6) Find the amount to be paid if David borrowed a sum of $5400 at 9% simple interest for 8 years.

(7) Susan took a loan of $5300 at the rate of 6% simple interest per annum. If he paid an amount of $7208 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due if Christopher borrowed a sum of $4000 at 6% simple interest for 3 years.

(9) What amount will be due after 2 years if David borrowed a sum of $3200 at a 5% simple interest?

(10) What amount does Linda have to pay after 5 years if he takes a loan of $3350 at 7% simple interest?