Simple Interest
Math MCQs

Question :    What amount does James have to pay after 6 years if he takes a loan of $3000 at 3% simple interest?

Correct Answer  $3540

Solution & Explanation

Solution

Given,

Principal (P) = $3000

Rate of Simple Interest (SI) = 3%

Time (t) = 6 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) = $3000 × 3% × 6

= $3000 ׳/₁₀₀ × 6

= ^{3000 × 3 × 6}/₁₀₀

= ^{9000 × 6}/₁₀₀

= ⁵⁴⁰⁰⁰/₁₀₀

= $540

Thus, Simple Interest = $540

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 + $540

= $3540

Thus, Amount to be paid = $3540 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) = 3%

And, Time (t) = 6 years

Thus, Amount (A)

= $3000 + ($3000 × 3% × 6)

= $3000 + ($3000 ׳/₁₀₀ × 6)

= $3000 + (^{3000 × 3 × 6}/₁₀₀)

= $3000 + (^{9000 × 6}/₁₀₀)

= $3000 + (⁵⁴⁰⁰⁰/₁₀₀)

= $3000 + $540 = $3540

Thus, Amount (A) to be paid = $3540 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 $3000, the simple interest in 1 year

= ³/₁₀₀ × 3000

= ^{3 × 3000}/₁₀₀

= ⁹⁰⁰⁰/₁₀₀ = $90

Thus, simple interest for 1 year = $90

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $90 × 6 = $540

Thus, Simple Interest (SI) = $540

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3000 + $540

= $3540

Thus, Amount to be paid = $3540 Answer

Similar Questions

(1) Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 6% simple interest.

(2) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 6% simple interest for 7 years.

(3) Calculate the amount due if Barbara borrowed a sum of $3550 at 3% simple interest for 4 years.

(4) Find the amount to be paid if Mary borrowed a sum of $5050 at 8% simple interest for 8 years.

(5) Mary took a loan of $4100 at the rate of 6% simple interest per annum. If he paid an amount of $6068 to clear the loan, then find the time period of the loan.

(6) If Jennifer paid $3900 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(7) Sarah took a loan of $5700 at the rate of 10% simple interest per annum. If he paid an amount of $9690 to clear the loan, then find the time period of the loan.

(8) In how much time a principal of $3150 will amount to $3528 at a simple interest of 3% per annum?

(9) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 8% simple interest for 4 years.

(10) Calculate the amount due if Christopher borrowed a sum of $4000 at 3% simple interest for 4 years.