Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Thomas borrowed a sum of $5800 at a rate of 8% simple interest.

Correct Answer  $10440

Solution & Explanation

Solution

Given,

Principal (P) = $5800

Rate of Simple Interest (SI) = 8%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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) = $5800 × 8% × 10

= $5800 ×⁸/₁₀₀ × 10

= ^{5800 × 8 × 10}/₁₀₀

= ^{46400 × 10}/₁₀₀

= ⁴⁶⁴⁰⁰⁰/₁₀₀

= $4640

Thus, Simple Interest = $4640

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 = $5800 + $4640

= $10440

Thus, Amount to be paid = $10440 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 = $5800

Rate of Simple Interest (SI) or (R) = 8%

And, Time (t) = 10 years

Thus, Amount (A)

= $5800 + ($5800 × 8% × 10)

= $5800 + ($5800 ×⁸/₁₀₀ × 10)

= $5800 + (^{5800 × 8 × 10}/₁₀₀)

= $5800 + (^{46400 × 10}/₁₀₀)

= $5800 + (⁴⁶⁴⁰⁰⁰/₁₀₀)

= $5800 + $4640 = $10440

Thus, Amount (A) to be paid = $10440 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = ⁸/₁₀₀

∴ For $5800, the simple interest in 1 year

= ⁸/₁₀₀ × 5800

= ^{8 × 5800}/₁₀₀

= ⁴⁶⁴⁰⁰/₁₀₀ = $464

Thus, simple interest for 1 year = $464

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $464 × 10 = $4640

Thus, Simple Interest (SI) = $4640

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5800 + $4640

= $10440

Thus, Amount to be paid = $10440 Answer

Similar Questions

(1) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 4% simple interest.

(2) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 10% simple interest.

(3) James took a loan of $4000 at the rate of 7% simple interest per annum. If he paid an amount of $6240 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due if Michael borrowed a sum of $3300 at 4% simple interest for 4 years.

(5) Find the amount to be paid if Michael borrowed a sum of $5300 at 6% simple interest for 7 years.

(6) Calculate the amount due if James borrowed a sum of $3000 at 9% simple interest for 3 years.

(7) Linda took a loan of $4700 at the rate of 10% simple interest per annum. If he paid an amount of $8930 to clear the loan, then find the time period of the loan.

(8) Find the amount to be paid if Charles borrowed a sum of $5900 at 7% simple interest for 8 years.

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

(10) Sarah took a loan of $5700 at the rate of 10% simple interest per annum. If he paid an amount of $9690 to clear the loan, then find the time period of the loan.