Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 3% simple interest.

Correct Answer  $6731

Solution & Explanation

Solution

Given,

Principal (P) = $5300

Rate of Simple Interest (SI) = 3%

Time (t) = 9 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) = $5300 × 3% × 9

= $5300 ׳/₁₀₀ × 9

= ^{5300 × 3 × 9}/₁₀₀

= ^{15900 × 9}/₁₀₀

= ¹⁴³¹⁰⁰/₁₀₀

= $1431

Thus, Simple Interest = $1431

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 = $5300 + $1431

= $6731

Thus, Amount to be paid = $6731 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 = $5300

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

And, Time (t) = 9 years

Thus, Amount (A)

= $5300 + ($5300 × 3% × 9)

= $5300 + ($5300 ׳/₁₀₀ × 9)

= $5300 + (^{5300 × 3 × 9}/₁₀₀)

= $5300 + (^{15900 × 9}/₁₀₀)

= $5300 + (¹⁴³¹⁰⁰/₁₀₀)

= $5300 + $1431 = $6731

Thus, Amount (A) to be paid = $6731 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 $5300, the simple interest in 1 year

= ³/₁₀₀ × 5300

= ^{3 × 5300}/₁₀₀

= ¹⁵⁹⁰⁰/₁₀₀ = $159

Thus, simple interest for 1 year = $159

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $159 × 9 = $1431

Thus, Simple Interest (SI) = $1431

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5300 + $1431

= $6731

Thus, Amount to be paid = $6731 Answer

Similar Questions

(1) In how much time a principal of $3000 will amount to $3600 at a simple interest of 5% per annum?

(2) Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 9% simple interest.

(3) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 6% simple interest?

(4) Calculate the amount due after 10 years if Mary borrowed a sum of $5050 at a rate of 9% simple interest.

(5) Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 10% simple interest.

(6) Nancy had to pay $4399 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(7) Find the amount to be paid if Karen borrowed a sum of $5950 at 5% simple interest for 8 years.

(8) Find the amount to be paid if David borrowed a sum of $5400 at 9% simple interest for 7 years.

(9) Calculate the amount due if Sarah borrowed a sum of $3850 at 6% simple interest for 4 years.

(10) What amount will be due after 2 years if William borrowed a sum of $3250 at a 7% simple interest?