Simple Interest
Math MCQs

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

Correct Answer  $9632

Solution & Explanation

Solution

Given,

Principal (P) = $5600

Rate of Simple Interest (SI) = 8%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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) = $5600 × 8% × 9

= $5600 ×⁸/₁₀₀ × 9

= ^{5600 × 8 × 9}/₁₀₀

= ^{44800 × 9}/₁₀₀

= ⁴⁰³²⁰⁰/₁₀₀

= $4032

Thus, Simple Interest = $4032

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 = $5600 + $4032

= $9632

Thus, Amount to be paid = $9632 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 = $5600

Rate of Simple Interest (SI) or (R) = 8%

And, Time (t) = 9 years

Thus, Amount (A)

= $5600 + ($5600 × 8% × 9)

= $5600 + ($5600 ×⁸/₁₀₀ × 9)

= $5600 + (^{5600 × 8 × 9}/₁₀₀)

= $5600 + (^{44800 × 9}/₁₀₀)

= $5600 + (⁴⁰³²⁰⁰/₁₀₀)

= $5600 + $4032 = $9632

Thus, Amount (A) to be paid = $9632 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = ⁸/₁₀₀

∴ For $5600, the simple interest in 1 year

= ⁸/₁₀₀ × 5600

= ^{8 × 5600}/₁₀₀

= ⁴⁴⁸⁰⁰/₁₀₀ = $448

Thus, simple interest for 1 year = $448

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $448 × 9 = $4032

Thus, Simple Interest (SI) = $4032

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5600 + $4032

= $9632

Thus, Amount to be paid = $9632 Answer

Similar Questions

(1) Elizabeth took a loan of $4900 at the rate of 10% simple interest per annum. If he paid an amount of $7840 to clear the loan, then find the time period of the loan.

(2) Find the amount to be paid if William borrowed a sum of $5500 at 2% simple interest for 7 years.

(3) Robert had to pay $3286 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(4) Find the amount to be paid if Thomas borrowed a sum of $5800 at 3% simple interest for 8 years.

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

(6) Calculate the amount due after 9 years if John borrowed a sum of $5200 at a rate of 9% simple interest.

(7) Calculate the amount due if Sarah borrowed a sum of $3850 at 7% simple interest for 3 years.

(8) Find the amount to be paid if Christopher borrowed a sum of $6000 at 9% simple interest for 8 years.

(9) Calculate the amount due if Robert borrowed a sum of $3100 at 4% simple interest for 3 years.

(10) Find the amount to be paid if Jessica borrowed a sum of $5750 at 5% simple interest for 7 years.