Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Mary borrowed a sum of $5050 at a rate of 3% simple interest.

Correct Answer  $6565

Solution & Explanation

Solution

Given,

Principal (P) = $5050

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) = $5050 × 3% × 10

= $5050 ׳/₁₀₀ × 10

= ^{5050 × 3 × 10}/₁₀₀

= ^{15150 × 10}/₁₀₀

= ¹⁵¹⁵⁰⁰/₁₀₀

= $1515

Thus, Simple Interest = $1515

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 = $5050 + $1515

= $6565

Thus, Amount to be paid = $6565 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 = $5050

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5050 + ($5050 × 3% × 10)

= $5050 + ($5050 ׳/₁₀₀ × 10)

= $5050 + (^{5050 × 3 × 10}/₁₀₀)

= $5050 + (^{15150 × 10}/₁₀₀)

= $5050 + (¹⁵¹⁵⁰⁰/₁₀₀)

= $5050 + $1515 = $6565

Thus, Amount (A) to be paid = $6565 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 $5050, the simple interest in 1 year

= ³/₁₀₀ × 5050

= ^{3 × 5050}/₁₀₀

= ¹⁵¹⁵⁰/₁₀₀ = $151.5

Thus, simple interest for 1 year = $151.5

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $151.5 × 10 = $1515

Thus, Simple Interest (SI) = $1515

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5050 + $1515

= $6565

Thus, Amount to be paid = $6565 Answer

Similar Questions

(1) Elizabeth had to pay $3657 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(2) How much loan did Ronald borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8625 to clear it?

(3) Margaret took a loan of $6700 at the rate of 8% simple interest per annum. If he paid an amount of $10452 to clear the loan, then find the time period of the loan.

(4) Betty had to pay $4505 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

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

(6) Barbara took a loan of $5100 at the rate of 6% simple interest per annum. If he paid an amount of $7854 to clear the loan, then find the time period of the loan.

(7) What amount does Michael have to pay after 5 years if he takes a loan of $3300 at 7% simple interest?

(8) Calculate the amount due after 9 years if Patricia borrowed a sum of $5150 at a rate of 8% simple interest.

(9) 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.

(10) Calculate the amount due if Linda borrowed a sum of $3350 at 6% simple interest for 4 years.