Simple Interest
Math MCQs

Question :    What amount does Richard have to pay after 6 years if he takes a loan of $3600 at 10% simple interest?

Correct Answer  $5760

Solution & Explanation

Solution

Given,

Principal (P) = $3600

Rate of Simple Interest (SI) = 10%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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) = $3600 × 10% × 6

= $3600 ×¹⁰/₁₀₀ × 6

= ^{3600 × 10 × 6}/₁₀₀

= ^{36000 × 6}/₁₀₀

= ²¹⁶⁰⁰⁰/₁₀₀

= $2160

Thus, Simple Interest = $2160

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 = $3600 + $2160

= $5760

Thus, Amount to be paid = $5760 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 = $3600

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 6 years

Thus, Amount (A)

= $3600 + ($3600 × 10% × 6)

= $3600 + ($3600 ×¹⁰/₁₀₀ × 6)

= $3600 + (^{3600 × 10 × 6}/₁₀₀)

= $3600 + (^{36000 × 6}/₁₀₀)

= $3600 + (²¹⁶⁰⁰⁰/₁₀₀)

= $3600 + $2160 = $5760

Thus, Amount (A) to be paid = $5760 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = ¹⁰/₁₀₀

∴ For $3600, the simple interest in 1 year

= ¹⁰/₁₀₀ × 3600

= ^{10 × 3600}/₁₀₀

= ³⁶⁰⁰⁰/₁₀₀ = $360

Thus, simple interest for 1 year = $360

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $360 × 6 = $2160

Thus, Simple Interest (SI) = $2160

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3600 + $2160

= $5760

Thus, Amount to be paid = $5760 Answer

Similar Questions

(1) Calculate the amount due after 10 years if Elizabeth borrowed a sum of $5450 at a rate of 8% simple interest.

(2) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 9% simple interest for 7 years.

(3) Christopher took a loan of $6000 at the rate of 8% simple interest per annum. If he paid an amount of $8880 to clear the loan, then find the time period of the loan.

(4) What amount will be due after 2 years if Joseph borrowed a sum of $3350 at a 4% simple interest?

(5) What amount does David have to pay after 6 years if he takes a loan of $3400 at 4% simple interest?

(6) Barbara took a loan of $5100 at the rate of 9% simple interest per annum. If he paid an amount of $9231 to clear the loan, then find the time period of the loan.

(7) If Joshua paid $5488 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(8) How much loan did Dorothy borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8337.5 to clear it?

(9) Mark took a loan of $6800 at the rate of 10% simple interest per annum. If he paid an amount of $12240 to clear the loan, then find the time period of the loan.

(10) What amount does Susan have to pay after 5 years if he takes a loan of $3650 at 8% simple interest?