Simple Interest
Math MCQs

Question :    Find the amount to be paid if Jennifer borrowed a sum of $5250 at 8% simple interest for 8 years.

Correct Answer  $8610

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 8%

Time (t) = 8 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% × 8

= $5250 ×⁸/₁₀₀ × 8

= ^{5250 × 8 × 8}/₁₀₀

= ^{42000 × 8}/₁₀₀

= ³³⁶⁰⁰⁰/₁₀₀

= $3360

Thus, Simple Interest = $3360

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 + $3360

= $8610

Thus, Amount to be paid = $8610 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) = 8 years

Thus, Amount (A)

= $5250 + ($5250 × 8% × 8)

= $5250 + ($5250 ×⁸/₁₀₀ × 8)

= $5250 + (^{5250 × 8 × 8}/₁₀₀)

= $5250 + (^{42000 × 8}/₁₀₀)

= $5250 + (³³⁶⁰⁰⁰/₁₀₀)

= $5250 + $3360 = $8610

Thus, Amount (A) to be paid = $8610 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 8 years

= Simple interest for 1 year × 8

= $420 × 8 = $3360

Thus, Simple Interest (SI) = $3360

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $3360

= $8610

Thus, Amount to be paid = $8610 Answer

Similar Questions

(1) Find the amount to be paid if Christopher borrowed a sum of $6000 at 5% simple interest for 7 years.

(2) Find the amount to be paid if Karen borrowed a sum of $5950 at 9% simple interest for 7 years.

(3) Matthew took a loan of $6400 at the rate of 7% simple interest per annum. If he paid an amount of $10432 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due if Mary borrowed a sum of $3050 at 2% simple interest for 4 years.

(5) If Steven paid $5520 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(6) Calculate the amount due after 10 years if Elizabeth borrowed a sum of $5450 at a rate of 4% simple interest.

(7) If Michelle paid $5346 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(8) How much loan did Thomas borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $7250 to clear it?

(9) Calculate the amount due after 9 years if Patricia borrowed a sum of $5150 at a rate of 6% simple interest.

(10) Find the amount to be paid if Jessica borrowed a sum of $5750 at 5% simple interest for 8 years.