Simple Interest
Math MCQs

Question :    What amount does Susan have to pay after 6 years if he takes a loan of $3650 at 4% simple interest?

Correct Answer  $4526

Solution & Explanation

Solution

Given,

Principal (P) = $3650

Rate of Simple Interest (SI) = 4%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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 × 4% × 6

= $3650 ×⁴/₁₀₀ × 6

= ^{3650 × 4 × 6}/₁₀₀

= ^{14600 × 6}/₁₀₀

= ⁸⁷⁶⁰⁰/₁₀₀

= $876

Thus, Simple Interest = $876

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 + $876

= $4526

Thus, Amount to be paid = $4526 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) = 4%

And, Time (t) = 6 years

Thus, Amount (A)

= $3650 + ($3650 × 4% × 6)

= $3650 + ($3650 ×⁴/₁₀₀ × 6)

= $3650 + (^{3650 × 4 × 6}/₁₀₀)

= $3650 + (^{14600 × 6}/₁₀₀)

= $3650 + (⁸⁷⁶⁰⁰/₁₀₀)

= $3650 + $876 = $4526

Thus, Amount (A) to be paid = $4526 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $3650, the simple interest in 1 year

= ⁴/₁₀₀ × 3650

= ^{4 × 3650}/₁₀₀

= ¹⁴⁶⁰⁰/₁₀₀ = $146

Thus, simple interest for 1 year = $146

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $146 × 6 = $876

Thus, Simple Interest (SI) = $876

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3650 + $876

= $4526

Thus, Amount to be paid = $4526 Answer

Similar Questions

(1) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 9% simple interest.

(2) Calculate the amount due if Thomas borrowed a sum of $3800 at 3% simple interest for 4 years.

(3) Sarah had to pay $4427.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(4) Find the amount to be paid if Christopher borrowed a sum of $6000 at 4% simple interest for 7 years.

(5) Calculate the amount due if John borrowed a sum of $3200 at 5% simple interest for 4 years.

(6) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 10% simple interest?

(7) Linda took a loan of $4700 at the rate of 10% simple interest per annum. If he paid an amount of $7990 to clear the loan, then find the time period of the loan.

(8) What amount does Mary have to pay after 6 years if he takes a loan of $3050 at 6% simple interest?

(9) If Anthony paid $5160 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(10) Sandra had to pay $4717 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.