Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 8% simple interest.

Correct Answer  $10234

Solution & Explanation

Solution

Given,

Principal (P) = $5950

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) = $5950 × 8% × 9

= $5950 ×⁸/₁₀₀ × 9

= ^{5950 × 8 × 9}/₁₀₀

= ^{47600 × 9}/₁₀₀

= ⁴²⁸⁴⁰⁰/₁₀₀

= $4284

Thus, Simple Interest = $4284

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 = $5950 + $4284

= $10234

Thus, Amount to be paid = $10234 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 = $5950

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

And, Time (t) = 9 years

Thus, Amount (A)

= $5950 + ($5950 × 8% × 9)

= $5950 + ($5950 ×⁸/₁₀₀ × 9)

= $5950 + (^{5950 × 8 × 9}/₁₀₀)

= $5950 + (^{47600 × 9}/₁₀₀)

= $5950 + (⁴²⁸⁴⁰⁰/₁₀₀)

= $5950 + $4284 = $10234

Thus, Amount (A) to be paid = $10234 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 $5950, the simple interest in 1 year

= ⁸/₁₀₀ × 5950

= ^{8 × 5950}/₁₀₀

= ⁴⁷⁶⁰⁰/₁₀₀ = $476

Thus, simple interest for 1 year = $476

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $476 × 9 = $4284

Thus, Simple Interest (SI) = $4284

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5950 + $4284

= $10234

Thus, Amount to be paid = $10234 Answer

Similar Questions

(1) How much loan did Stephanie borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8682.5 to clear it?

(2) Robert took a loan of $4200 at the rate of 6% simple interest per annum. If he paid an amount of $6468 to clear the loan, then find the time period of the loan.

(3) What amount does Charles have to pay after 6 years if he takes a loan of $3900 at 9% simple interest?

(4) What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 9% simple interest?

(5) Calculate the amount due after 9 years if Linda borrowed a sum of $5350 at a rate of 10% simple interest.

(6) What amount does David have to pay after 5 years if he takes a loan of $3400 at 3% simple interest?

(7) In how much time a principal of $3000 will amount to $3270 at a simple interest of 3% per annum?

(8) Jessica took a loan of $5500 at the rate of 8% simple interest per annum. If he paid an amount of $9460 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due if Joseph borrowed a sum of $3700 at 3% simple interest for 4 years.

(10) If Andrew paid $5568 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.