Simple Interest
Math MCQs

Question :    Find the amount to be paid if Susan borrowed a sum of $5650 at 3% simple interest for 8 years.

Correct Answer  $7006

Solution & Explanation

Solution

Given,

Principal (P) = $5650

Rate of Simple Interest (SI) = 3%

Time (t) = 8 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) = $5650 × 3% × 8

= $5650 ׳/₁₀₀ × 8

= ^{5650 × 3 × 8}/₁₀₀

= ^{16950 × 8}/₁₀₀

= ¹³⁵⁶⁰⁰/₁₀₀

= $1356

Thus, Simple Interest = $1356

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 = $5650 + $1356

= $7006

Thus, Amount to be paid = $7006 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 = $5650

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

And, Time (t) = 8 years

Thus, Amount (A)

= $5650 + ($5650 × 3% × 8)

= $5650 + ($5650 ׳/₁₀₀ × 8)

= $5650 + (^{5650 × 3 × 8}/₁₀₀)

= $5650 + (^{16950 × 8}/₁₀₀)

= $5650 + (¹³⁵⁶⁰⁰/₁₀₀)

= $5650 + $1356 = $7006

Thus, Amount (A) to be paid = $7006 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 $5650, the simple interest in 1 year

= ³/₁₀₀ × 5650

= ^{3 × 5650}/₁₀₀

= ¹⁶⁹⁵⁰/₁₀₀ = $169.5

Thus, simple interest for 1 year = $169.5

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $169.5 × 8 = $1356

Thus, Simple Interest (SI) = $1356

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5650 + $1356

= $7006

Thus, Amount to be paid = $7006 Answer

Similar Questions

(1) Karen took a loan of $5900 at the rate of 6% simple interest per annum. If he paid an amount of $9086 to clear the loan, then find the time period of the loan.

(2) Karen took a loan of $5900 at the rate of 10% simple interest per annum. If he paid an amount of $11210 to clear the loan, then find the time period of the loan.

(3) Christopher took a loan of $6000 at the rate of 10% simple interest per annum. If he paid an amount of $9600 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due after 10 years if Linda borrowed a sum of $5350 at a rate of 10% simple interest.

(5) What amount does Joseph have to pay after 6 years if he takes a loan of $3700 at 6% simple interest?

(6) If Michelle paid $5742 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(7) Calculate the amount due after 9 years if Jessica borrowed a sum of $5750 at a rate of 3% simple interest.

(8) Calculate the amount due if Jessica borrowed a sum of $3750 at 7% simple interest for 4 years.

(9) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 10% simple interest.

(10) Charles took a loan of $5800 at the rate of 6% simple interest per annum. If he paid an amount of $8236 to clear the loan, then find the time period of the loan.