Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if John borrowed a sum of $5200 at a rate of 2% simple interest.

Correct Answer  $6136

Solution & Explanation

Solution

Given,

Principal (P) = $5200

Rate of Simple Interest (SI) = 2%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 2% simple interest means, Rate of Simple Interest (SI) is 2% 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) = $5200 × 2% × 9

= $5200 ײ/₁₀₀ × 9

= ^{5200 × 2 × 9}/₁₀₀

= ^{10400 × 9}/₁₀₀

= ⁹³⁶⁰⁰/₁₀₀

= $936

Thus, Simple Interest = $936

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 = $5200 + $936

= $6136

Thus, Amount to be paid = $6136 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 = $5200

Rate of Simple Interest (SI) or (R) = 2%

And, Time (t) = 9 years

Thus, Amount (A)

= $5200 + ($5200 × 2% × 9)

= $5200 + ($5200 ײ/₁₀₀ × 9)

= $5200 + (^{5200 × 2 × 9}/₁₀₀)

= $5200 + (^{10400 × 9}/₁₀₀)

= $5200 + (⁹³⁶⁰⁰/₁₀₀)

= $5200 + $936 = $6136

Thus, Amount (A) to be paid = $6136 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 2%

This, means, $2 per $100 per year

∵ For $100, the simple interest for 1 year = $2

∴ For $1, the simple interest for 1 year = ²/₁₀₀

∴ For $5200, the simple interest in 1 year

= ²/₁₀₀ × 5200

= ^{2 × 5200}/₁₀₀

= ¹⁰⁴⁰⁰/₁₀₀ = $104

Thus, simple interest for 1 year = $104

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $104 × 9 = $936

Thus, Simple Interest (SI) = $936

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5200 + $936

= $6136

Thus, Amount to be paid = $6136 Answer

Similar Questions

(1) In how much time a principal of $3150 will amount to $3339 at a simple interest of 3% per annum?

(2) How much loan did Amanda borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8937.5 to clear it?

(3) Find the amount to be paid if Charles borrowed a sum of $5900 at 10% simple interest for 8 years.

(4) Calculate the amount due if Thomas borrowed a sum of $3800 at 5% simple interest for 4 years.

(5) How much loan did Sarah borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6727.5 to clear it?

(6) Daniel took a loan of $6200 at the rate of 8% simple interest per annum. If he paid an amount of $10664 to clear the loan, then find the time period of the loan.

(7) Betty took a loan of $6500 at the rate of 6% simple interest per annum. If he paid an amount of $8840 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 3% simple interest.

(9) Steven had to pay $5290 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(10) Calculate the amount due after 9 years if Barbara borrowed a sum of $5550 at a rate of 3% simple interest.