Simple Interest
Math MCQs

Question :    Calculate the amount due if Michael borrowed a sum of $3300 at 7% simple interest for 3 years.

Correct Answer  $3993

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 7%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 7% simple interest means, Rate of Simple Interest (SI) is 7% 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 × 7% × 3

= $3300 ×⁷/₁₀₀ × 3

= ^{3300 × 7 × 3}/₁₀₀

= ^{23100 × 3}/₁₀₀

= ⁶⁹³⁰⁰/₁₀₀

= $693

Thus, Simple Interest = $693

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 + $693

= $3993

Thus, Amount to be paid = $3993 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) = 7%

And, Time (t) = 3 years

Thus, Amount (A)

= $3300 + ($3300 × 7% × 3)

= $3300 + ($3300 ×⁷/₁₀₀ × 3)

= $3300 + (^{3300 × 7 × 3}/₁₀₀)

= $3300 + (^{23100 × 3}/₁₀₀)

= $3300 + (⁶⁹³⁰⁰/₁₀₀)

= $3300 + $693 = $3993

Thus, Amount (A) to be paid = $3993 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 7%

This, means, $7 per $100 per year

∵ For $100, the simple interest for 1 year = $7

∴ For $1, the simple interest for 1 year = ⁷/₁₀₀

∴ For $3300, the simple interest in 1 year

= ⁷/₁₀₀ × 3300

= ^{7 × 3300}/₁₀₀

= ²³¹⁰⁰/₁₀₀ = $231

Thus, simple interest for 1 year = $231

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $231 × 3 = $693

Thus, Simple Interest (SI) = $693

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $693

= $3993

Thus, Amount to be paid = $3993 Answer

Similar Questions

(1) If Margaret paid $4872 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(2) Find the amount to be paid if Susan borrowed a sum of $5650 at 10% simple interest for 8 years.

(3) Joseph took a loan of $5400 at the rate of 6% simple interest per annum. If he paid an amount of $8316 to clear the loan, then find the time period of the loan.

(4) Jessica took a loan of $5500 at the rate of 7% simple interest per annum. If he paid an amount of $8580 to clear the loan, then find the time period of the loan.

(5) Jennifer took a loan of $4500 at the rate of 9% simple interest per annum. If he paid an amount of $7335 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Charles borrowed a sum of $3900 at 2% simple interest for 3 years.

(7) What amount will be due after 2 years if David borrowed a sum of $3200 at a 7% simple interest?

(8) If Daniel paid $4920 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(9) Find the amount to be paid if Linda borrowed a sum of $5350 at 5% simple interest for 8 years.

(10) Calculate the amount due after 10 years if Thomas borrowed a sum of $5800 at a rate of 10% simple interest.