Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Charles borrowed a sum of $5900 at a rate of 8% simple interest.

Correct Answer  $10148

Solution & Explanation

Solution

Given,

Principal (P) = $5900

Rate of Simple Interest (SI) = 8%

Time (t) = 9 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% × 9

= $5900 ×⁸/₁₀₀ × 9

= ^{5900 × 8 × 9}/₁₀₀

= ^{47200 × 9}/₁₀₀

= ⁴²⁴⁸⁰⁰/₁₀₀

= $4248

Thus, Simple Interest = $4248

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 + $4248

= $10148

Thus, Amount to be paid = $10148 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) = 9 years

Thus, Amount (A)

= $5900 + ($5900 × 8% × 9)

= $5900 + ($5900 ×⁸/₁₀₀ × 9)

= $5900 + (^{5900 × 8 × 9}/₁₀₀)

= $5900 + (^{47200 × 9}/₁₀₀)

= $5900 + (⁴²⁴⁸⁰⁰/₁₀₀)

= $5900 + $4248 = $10148

Thus, Amount (A) to be paid = $10148 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 9 years

= Simple interest for 1 year × 9

= $472 × 9 = $4248

Thus, Simple Interest (SI) = $4248

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5900 + $4248

= $10148

Thus, Amount to be paid = $10148 Answer

Similar Questions

(1) Calculate the amount due if Richard borrowed a sum of $3600 at 6% simple interest for 4 years.

(2) James took a loan of $4000 at the rate of 7% simple interest per annum. If he paid an amount of $5960 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due if Jennifer borrowed a sum of $3250 at 2% simple interest for 3 years.

(4) What amount will be due after 2 years if William borrowed a sum of $3250 at a 7% simple interest?

(5) Calculate the amount due if Richard borrowed a sum of $3600 at 10% simple interest for 4 years.

(6) Daniel had to pay $4469 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(7) Calculate the amount due after 9 years if Jessica borrowed a sum of $5750 at a rate of 8% simple interest.

(8) Betty took a loan of $6500 at the rate of 6% simple interest per annum. If he paid an amount of $8840 to clear the loan, then find the time period of the loan.

(9) Find the amount to be paid if Sarah borrowed a sum of $5850 at 10% simple interest for 7 years.

(10) How much loan did Daniel borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7320 to clear it?