Simple Interest
Math MCQs

Question :    What amount does James have to pay after 6 years if he takes a loan of $3000 at 10% simple interest?

Correct Answer  $4800

Solution & Explanation

Solution

Given,

Principal (P) = $3000

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) = $3000 × 10% × 6

= $3000 ×¹⁰/₁₀₀ × 6

= ^{3000 × 10 × 6}/₁₀₀

= ^{30000 × 6}/₁₀₀

= ¹⁸⁰⁰⁰⁰/₁₀₀

= $1800

Thus, Simple Interest = $1800

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 = $3000 + $1800

= $4800

Thus, Amount to be paid = $4800 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 = $3000

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

And, Time (t) = 6 years

Thus, Amount (A)

= $3000 + ($3000 × 10% × 6)

= $3000 + ($3000 ×¹⁰/₁₀₀ × 6)

= $3000 + (^{3000 × 10 × 6}/₁₀₀)

= $3000 + (^{30000 × 6}/₁₀₀)

= $3000 + (¹⁸⁰⁰⁰⁰/₁₀₀)

= $3000 + $1800 = $4800

Thus, Amount (A) to be paid = $4800 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 $3000, the simple interest in 1 year

= ¹⁰/₁₀₀ × 3000

= ^{10 × 3000}/₁₀₀

= ³⁰⁰⁰⁰/₁₀₀ = $300

Thus, simple interest for 1 year = $300

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $300 × 6 = $1800

Thus, Simple Interest (SI) = $1800

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3000 + $1800

= $4800

Thus, Amount to be paid = $4800 Answer

Similar Questions

(1) William had to pay $3710 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(2) Anthony took a loan of $6600 at the rate of 7% simple interest per annum. If he paid an amount of $10296 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 4% simple interest.

(4) In how much time a principal of $3050 will amount to $3538 at a simple interest of 4% per annum?

(5) Calculate the amount due if Mary borrowed a sum of $3050 at 6% simple interest for 4 years.

(6) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 3% simple interest.

(7) What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 5% simple interest?

(8) Find the amount to be paid if Christopher borrowed a sum of $6000 at 6% simple interest for 7 years.

(9) Anthony took a loan of $6600 at the rate of 10% simple interest per annum. If he paid an amount of $11220 to clear the loan, then find the time period of the loan.

(10) If Joshua paid $5880 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.