Simple Interest
Math MCQs

Question :    Calculate the amount due if William borrowed a sum of $3500 at 3% simple interest for 3 years.

Correct Answer  $3815

Solution & Explanation

Solution

Given,

Principal (P) = $3500

Rate of Simple Interest (SI) = 3%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $3500 × 3% × 3

= $3500 ׳/₁₀₀ × 3

= ^{3500 × 3 × 3}/₁₀₀

= ^{10500 × 3}/₁₀₀

= ³¹⁵⁰⁰/₁₀₀

= $315

Thus, Simple Interest = $315

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 = $3500 + $315

= $3815

Thus, Amount to be paid = $3815 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 = $3500

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 3 years

Thus, Amount (A)

= $3500 + ($3500 × 3% × 3)

= $3500 + ($3500 ׳/₁₀₀ × 3)

= $3500 + (^{3500 × 3 × 3}/₁₀₀)

= $3500 + (^{10500 × 3}/₁₀₀)

= $3500 + (³¹⁵⁰⁰/₁₀₀)

= $3500 + $315 = $3815

Thus, Amount (A) to be paid = $3815 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = ³/₁₀₀

∴ For $3500, the simple interest in 1 year

= ³/₁₀₀ × 3500

= ^{3 × 3500}/₁₀₀

= ¹⁰⁵⁰⁰/₁₀₀ = $105

Thus, simple interest for 1 year = $105

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $105 × 3 = $315

Thus, Simple Interest (SI) = $315

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3500 + $315

= $3815

Thus, Amount to be paid = $3815 Answer

Similar Questions

(1) Thomas took a loan of $5600 at the rate of 6% simple interest per annum. If he paid an amount of $7616 to clear the loan, then find the time period of the loan.

(2) Sandra had to pay $4984 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

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

(4) Find the amount to be paid if Susan borrowed a sum of $5650 at 6% simple interest for 8 years.

(5) What amount does Joseph have to pay after 6 years if he takes a loan of $3700 at 6% simple interest?

(6) Margaret took a loan of $6700 at the rate of 8% simple interest per annum. If he paid an amount of $11524 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 10% simple interest for 3 years.

(8) If Joseph paid $4440 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(9) Donald had to pay $4770 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(10) What amount does David have to pay after 5 years if he takes a loan of $3400 at 4% simple interest?