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) What amount does John have to pay after 6 years if he takes a loan of $3200 at 7% simple interest?

(2) Calculate the amount due if David borrowed a sum of $3400 at 8% simple interest for 3 years.

(3) Daniel took a loan of $6200 at the rate of 6% simple interest per annum. If he paid an amount of $8804 to clear the loan, then find the time period of the loan.

(4) Find the amount to be paid if Mary borrowed a sum of $5050 at 2% simple interest for 7 years.

(5) If Robert borrowed $3100 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(6) David took a loan of $4800 at the rate of 7% simple interest per annum. If he paid an amount of $6816 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due if Mary borrowed a sum of $3050 at 3% simple interest for 4 years.

(8) Find the amount to be paid if Mary borrowed a sum of $5050 at 10% simple interest for 7 years.

(9) What amount does William have to pay after 6 years if he takes a loan of $3500 at 7% simple interest?

(10) Nancy took a loan of $6300 at the rate of 10% simple interest per annum. If he paid an amount of $10710 to clear the loan, then find the time period of the loan.