Simple Interest
Math MCQs

Question :    What amount does Michael have to pay after 6 years if he takes a loan of $3300 at 3% simple interest?

Correct Answer  $3894

Solution & Explanation

Solution

Given,

Principal (P) = $3300

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) = $3300 × 3% × 6

= $3300 ׳/₁₀₀ × 6

= ^{3300 × 3 × 6}/₁₀₀

= ^{9900 × 6}/₁₀₀

= ⁵⁹⁴⁰⁰/₁₀₀

= $594

Thus, Simple Interest = $594

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 = $3300 + $594

= $3894

Thus, Amount to be paid = $3894 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 = $3300

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 6 years

Thus, Amount (A)

= $3300 + ($3300 × 3% × 6)

= $3300 + ($3300 ׳/₁₀₀ × 6)

= $3300 + (^{3300 × 3 × 6}/₁₀₀)

= $3300 + (^{9900 × 6}/₁₀₀)

= $3300 + (⁵⁹⁴⁰⁰/₁₀₀)

= $3300 + $594 = $3894

Thus, Amount (A) to be paid = $3894 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 $3300, the simple interest in 1 year

= ³/₁₀₀ × 3300

= ^{3 × 3300}/₁₀₀

= ⁹⁹⁰⁰/₁₀₀ = $99

Thus, simple interest for 1 year = $99

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $99 × 6 = $594

Thus, Simple Interest (SI) = $594

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $594

= $3894

Thus, Amount to be paid = $3894 Answer

Similar Questions

(1) What amount will be due after 2 years if Christopher borrowed a sum of $3500 at a 7% simple interest?

(2) In how much time a principal of $3050 will amount to $3355 at a simple interest of 5% per annum?

(3) What amount does James have to pay after 5 years if he takes a loan of $3000 at 7% simple interest?

(4) Calculate the amount due if Sarah borrowed a sum of $3850 at 10% simple interest for 3 years.

(5) Calculate the amount due if James borrowed a sum of $3000 at 10% simple interest for 3 years.

(6) Susan took a loan of $5300 at the rate of 9% simple interest per annum. If he paid an amount of $9116 to clear the loan, then find the time period of the loan.

(7) How much loan did Jeffrey borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8580 to clear it?

(8) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 9% simple interest.

(9) Find the amount to be paid if John borrowed a sum of $5200 at 7% simple interest for 8 years.

(10) Find the amount to be paid if Thomas borrowed a sum of $5800 at 4% simple interest for 8 years.