Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Jennifer borrowed a sum of $5250 at a rate of 8% simple interest.

Correct Answer  $9450

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 8%

Time (t) = 10 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) = $5250 × 8% × 10

= $5250 ×⁸/₁₀₀ × 10

= ^{5250 × 8 × 10}/₁₀₀

= ^{42000 × 10}/₁₀₀

= ⁴²⁰⁰⁰⁰/₁₀₀

= $4200

Thus, Simple Interest = $4200

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 = $5250 + $4200

= $9450

Thus, Amount to be paid = $9450 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 = $5250

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5250 + ($5250 × 8% × 10)

= $5250 + ($5250 ×⁸/₁₀₀ × 10)

= $5250 + (^{5250 × 8 × 10}/₁₀₀)

= $5250 + (^{42000 × 10}/₁₀₀)

= $5250 + (⁴²⁰⁰⁰⁰/₁₀₀)

= $5250 + $4200 = $9450

Thus, Amount (A) to be paid = $9450 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 $5250, the simple interest in 1 year

= ⁸/₁₀₀ × 5250

= ^{8 × 5250}/₁₀₀

= ⁴²⁰⁰⁰/₁₀₀ = $420

Thus, simple interest for 1 year = $420

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $420 × 10 = $4200

Thus, Simple Interest (SI) = $4200

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $4200

= $9450

Thus, Amount to be paid = $9450 Answer

Similar Questions

(1) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $7224 to clear the loan, then find the time period of the loan.

(2) Find the amount to be paid if Patricia borrowed a sum of $5150 at 7% simple interest for 8 years.

(3) If Donna paid $5626 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(4) Calculate the amount due if Jennifer borrowed a sum of $3250 at 8% simple interest for 4 years.

(5) Christopher took a loan of $6000 at the rate of 10% simple interest per annum. If he paid an amount of $11400 to clear the loan, then find the time period of the loan.

(6) Matthew had to pay $4452 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(7) Calculate the amount due if Thomas borrowed a sum of $3800 at 9% simple interest for 4 years.

(8) Lisa took a loan of $6100 at the rate of 9% simple interest per annum. If he paid an amount of $9943 to clear the loan, then find the time period of the loan.

(9) How much loan did Rebecca borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8415 to clear it?

(10) Calculate the amount due if John borrowed a sum of $3200 at 3% simple interest for 3 years.