Simple Interest
Math MCQs

Question :    Find the amount to be paid if Robert borrowed a sum of $5100 at 2% simple interest for 7 years.

Correct Answer  $5814

Solution & Explanation

Solution

Given,

Principal (P) = $5100

Rate of Simple Interest (SI) = 2%

Time (t) = 7 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) = $5100 × 2% × 7

= $5100 ײ/₁₀₀ × 7

= ^{5100 × 2 × 7}/₁₀₀

= ^{10200 × 7}/₁₀₀

= ⁷¹⁴⁰⁰/₁₀₀

= $714

Thus, Simple Interest = $714

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 = $5100 + $714

= $5814

Thus, Amount to be paid = $5814 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 = $5100

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

And, Time (t) = 7 years

Thus, Amount (A)

= $5100 + ($5100 × 2% × 7)

= $5100 + ($5100 ײ/₁₀₀ × 7)

= $5100 + (^{5100 × 2 × 7}/₁₀₀)

= $5100 + (^{10200 × 7}/₁₀₀)

= $5100 + (⁷¹⁴⁰⁰/₁₀₀)

= $5100 + $714 = $5814

Thus, Amount (A) to be paid = $5814 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 $5100, the simple interest in 1 year

= ²/₁₀₀ × 5100

= ^{2 × 5100}/₁₀₀

= ¹⁰²⁰⁰/₁₀₀ = $102

Thus, simple interest for 1 year = $102

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $102 × 7 = $714

Thus, Simple Interest (SI) = $714

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5100 + $714

= $5814

Thus, Amount to be paid = $5814 Answer

Similar Questions

(1) Find the amount to be paid if Linda borrowed a sum of $5350 at 6% simple interest for 8 years.

(2) William took a loan of $5000 at the rate of 6% simple interest per annum. If he paid an amount of $7400 to clear the loan, then find the time period of the loan.

(3) What amount does John have to pay after 6 years if he takes a loan of $3200 at 10% simple interest?

(4) What amount does Christopher have to pay after 6 years if he takes a loan of $4000 at 6% simple interest?

(5) Calculate the amount due if Charles borrowed a sum of $3900 at 8% simple interest for 3 years.

(6) Calculate the amount due if Jennifer borrowed a sum of $3250 at 6% simple interest for 3 years.

(7) If Mary borrowed $3050 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(8) Calculate the amount due if Christopher borrowed a sum of $4000 at 6% simple interest for 4 years.

(9) Mark took a loan of $6800 at the rate of 9% simple interest per annum. If he paid an amount of $12308 to clear the loan, then find the time period of the loan.

(10) Joseph took a loan of $5400 at the rate of 7% simple interest per annum. If he paid an amount of $8802 to clear the loan, then find the time period of the loan.