Simple Interest
Math MCQs

Question :    What amount will be due after 2 years if Anthony borrowed a sum of $3650 at a 9% simple interest?

Correct Answer  $4307

Solution & Explanation

Solution

Given,

Principal (P) = $3650

Rate of Simple Interest (SI) = 9%

Time (t) = 2 years

Thus, Amount (A) = ?

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

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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) = $3650 × 9% × 2

= $3650 ×⁹/₁₀₀ × 2

= ^{3650 × 9 × 2}/₁₀₀

= ^{32850 × 2}/₁₀₀

= ⁶⁵⁷⁰⁰/₁₀₀

= $657

Thus, Simple Interest = $657

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 = $3650 + $657

= $4307

Thus, Amount to be paid = $4307 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 = $3650

Rate of Simple Interest (SI) or (R) = 9%

And, Time (t) = 2 years

Thus, Amount (A)

= $3650 + ($3650 × 9% × 2)

= $3650 + ($3650 ×⁹/₁₀₀ × 2)

= $3650 + (^{3650 × 9 × 2}/₁₀₀)

= $3650 + (^{32850 × 2}/₁₀₀)

= $3650 + (⁶⁵⁷⁰⁰/₁₀₀)

= $3650 + $657 = $4307

Thus, Amount (A) to be paid = $4307 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = ⁹/₁₀₀

∴ For $3650, the simple interest in 1 year

= ⁹/₁₀₀ × 3650

= ^{9 × 3650}/₁₀₀

= ³²⁸⁵⁰/₁₀₀ = $328.5

Thus, simple interest for 1 year = $328.5

Therefore, simple interest for 2 years

= Simple interest for 1 year × 2

= $328.5 × 2 = $657

Thus, Simple Interest (SI) = $657

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3650 + $657

= $4307

Thus, Amount to be paid = $4307 Answer

Similar Questions

(1) Find the amount to be paid if Patricia borrowed a sum of $5150 at 5% simple interest for 7 years.

(2) Calculate the amount due after 9 years if Joseph borrowed a sum of $5700 at a rate of 9% simple interest.

(3) If William paid $4060 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(4) Donald took a loan of $7000 at the rate of 10% simple interest per annum. If he paid an amount of $11900 to clear the loan, then find the time period of the loan.

(5) Find the amount to be paid if Susan borrowed a sum of $5650 at 4% simple interest for 7 years.

(6) How much loan did Ashley borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7860 to clear it?

(7) Find the amount to be paid if John borrowed a sum of $5200 at 5% simple interest for 7 years.

(8) If John paid $3584 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(9) Calculate the amount due if David borrowed a sum of $3400 at 10% simple interest for 4 years.

(10) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 10% simple interest for 4 years.