Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Charles borrowed a sum of $5900 at a rate of 8% simple interest.

Correct Answer  $10620

Solution & Explanation

Solution

Given,

Principal (P) = $5900

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) = $5900 × 8% × 10

= $5900 ×⁸/₁₀₀ × 10

= ^{5900 × 8 × 10}/₁₀₀

= ^{47200 × 10}/₁₀₀

= ⁴⁷²⁰⁰⁰/₁₀₀

= $4720

Thus, Simple Interest = $4720

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 = $5900 + $4720

= $10620

Thus, Amount to be paid = $10620 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 = $5900

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5900 + ($5900 × 8% × 10)

= $5900 + ($5900 ×⁸/₁₀₀ × 10)

= $5900 + (^{5900 × 8 × 10}/₁₀₀)

= $5900 + (^{47200 × 10}/₁₀₀)

= $5900 + (⁴⁷²⁰⁰⁰/₁₀₀)

= $5900 + $4720 = $10620

Thus, Amount (A) to be paid = $10620 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 $5900, the simple interest in 1 year

= ⁸/₁₀₀ × 5900

= ^{8 × 5900}/₁₀₀

= ⁴⁷²⁰⁰/₁₀₀ = $472

Thus, simple interest for 1 year = $472

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $472 × 10 = $4720

Thus, Simple Interest (SI) = $4720

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5900 + $4720

= $10620

Thus, Amount to be paid = $10620 Answer

Similar Questions

(1) Richard took a loan of $5200 at the rate of 10% simple interest per annum. If he paid an amount of $8840 to clear the loan, then find the time period of the loan.

(2) If Robert paid $3348 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(3) Calculate the amount due if Karen borrowed a sum of $3950 at 7% simple interest for 4 years.

(4) Calculate the amount due after 10 years if Michael borrowed a sum of $5300 at a rate of 7% simple interest.

(5) What amount does Barbara have to pay after 5 years if he takes a loan of $3550 at 4% simple interest?

(6) How much loan did Melissa borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $8820 to clear it?

(7) Nancy took a loan of $6300 at the rate of 7% simple interest per annum. If he paid an amount of $8946 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due if Jennifer borrowed a sum of $3250 at 2% simple interest for 4 years.

(9) How much loan did Paul borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7705 to clear it?

(10) Calculate the amount due if Charles borrowed a sum of $3900 at 6% simple interest for 4 years.