Simple Interest
Math MCQs

Question :    What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 8% simple interest?

Correct Answer  $3538

Solution & Explanation

Solution

Given,

Principal (P) = $3050

Rate of Simple Interest (SI) = 8%

Time (t) = 2 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) = $3050 × 8% × 2

= $3050 ×⁸/₁₀₀ × 2

= ^{3050 × 8 × 2}/₁₀₀

= ^{24400 × 2}/₁₀₀

= ⁴⁸⁸⁰⁰/₁₀₀

= $488

Thus, Simple Interest = $488

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 = $3050 + $488

= $3538

Thus, Amount to be paid = $3538 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 = $3050

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

And, Time (t) = 2 years

Thus, Amount (A)

= $3050 + ($3050 × 8% × 2)

= $3050 + ($3050 ×⁸/₁₀₀ × 2)

= $3050 + (^{3050 × 8 × 2}/₁₀₀)

= $3050 + (^{24400 × 2}/₁₀₀)

= $3050 + (⁴⁸⁸⁰⁰/₁₀₀)

= $3050 + $488 = $3538

Thus, Amount (A) to be paid = $3538 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 $3050, the simple interest in 1 year

= ⁸/₁₀₀ × 3050

= ^{8 × 3050}/₁₀₀

= ²⁴⁴⁰⁰/₁₀₀ = $244

Thus, simple interest for 1 year = $244

Therefore, simple interest for 2 years

= Simple interest for 1 year × 2

= $244 × 2 = $488

Thus, Simple Interest (SI) = $488

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3050 + $488

= $3538

Thus, Amount to be paid = $3538 Answer

Similar Questions

(1) Joseph took a loan of $5400 at the rate of 6% simple interest per annum. If he paid an amount of $8316 to clear the loan, then find the time period of the loan.

(2) Michael took a loan of $4600 at the rate of 8% simple interest per annum. If he paid an amount of $6808 to clear the loan, then find the time period of the loan.

(3) Sarah took a loan of $5700 at the rate of 9% simple interest per annum. If he paid an amount of $10830 to clear the loan, then find the time period of the loan.

(4) How much loan did Anthony borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $7875 to clear it?

(5) In how much time a principal of $3000 will amount to $3240 at a simple interest of 4% per annum?

(6) How much loan did Mark borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7360 to clear it?

(7) If Matthew paid $4872 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(8) How much loan did Edward borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $9500 to clear it?

(9) Matthew took a loan of $6400 at the rate of 8% simple interest per annum. If he paid an amount of $11520 to clear the loan, then find the time period of the loan.

(10) If Charles paid $4368 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.