Simple Interest
Math MCQs

Question :    Find the amount to be paid if Barbara borrowed a sum of $5550 at 8% simple interest for 8 years.

Correct Answer  $9102

Solution & Explanation

Solution

Given,

Principal (P) = $5550

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) = $5550 × 8% × 8

= $5550 ×⁸/₁₀₀ × 8

= ^{5550 × 8 × 8}/₁₀₀

= ^{44400 × 8}/₁₀₀

= ³⁵⁵²⁰⁰/₁₀₀

= $3552

Thus, Simple Interest = $3552

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 = $5550 + $3552

= $9102

Thus, Amount to be paid = $9102 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 = $5550

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

And, Time (t) = 8 years

Thus, Amount (A)

= $5550 + ($5550 × 8% × 8)

= $5550 + ($5550 ×⁸/₁₀₀ × 8)

= $5550 + (^{5550 × 8 × 8}/₁₀₀)

= $5550 + (^{44400 × 8}/₁₀₀)

= $5550 + (³⁵⁵²⁰⁰/₁₀₀)

= $5550 + $3552 = $9102

Thus, Amount (A) to be paid = $9102 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 $5550, the simple interest in 1 year

= ⁸/₁₀₀ × 5550

= ^{8 × 5550}/₁₀₀

= ⁴⁴⁴⁰⁰/₁₀₀ = $444

Thus, simple interest for 1 year = $444

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $444 × 8 = $3552

Thus, Simple Interest (SI) = $3552

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5550 + $3552

= $9102

Thus, Amount to be paid = $9102 Answer

Similar Questions

(1) If Robert paid $3348 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(2) Linda took a loan of $4700 at the rate of 7% simple interest per annum. If he paid an amount of $7661 to clear the loan, then find the time period of the loan.

(3) Find the amount to be paid if David borrowed a sum of $5400 at 2% simple interest for 8 years.

(4) Joseph took a loan of $5400 at the rate of 6% simple interest per annum. If he paid an amount of $8640 to clear the loan, then find the time period of the loan.

(5) In how much time a principal of $3050 will amount to $3294 at a simple interest of 4% per annum?

(6) How much loan did Anthony borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7245 to clear it?

(7) What amount will be due after 2 years if Joshua borrowed a sum of $3950 at a 9% simple interest?

(8) Calculate the amount due after 10 years if William borrowed a sum of $5500 at a rate of 10% simple interest.

(9) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 7% simple interest for 7 years.

(10) Find the amount to be paid if Susan borrowed a sum of $5650 at 4% simple interest for 8 years.