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 Patricia paid $3780 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(2) In how much time a principal of $3000 will amount to $3240 at a simple interest of 2% per annum?

(3) Michael took a loan of $4600 at the rate of 8% simple interest per annum. If he paid an amount of $7912 to clear the loan, then find the time period of the loan.

(4) What amount will be due after 2 years if Matthew borrowed a sum of $3600 at a 10% simple interest?

(5) Calculate the amount due if Christopher borrowed a sum of $4000 at 5% simple interest for 3 years.

(6) Elizabeth took a loan of $4900 at the rate of 6% simple interest per annum. If he paid an amount of $7252 to clear the loan, then find the time period of the loan.

(7) If Ashley paid $4914 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(8) Nancy took a loan of $6300 at the rate of 6% simple interest per annum. If he paid an amount of $9702 to clear the loan, then find the time period of the loan.

(9) If Charles borrowed $3900 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(10) Calculate the amount due if Karen borrowed a sum of $3950 at 5% simple interest for 4 years.