Simple Interest
Math MCQs

Question :    Find the amount to be paid if Patricia borrowed a sum of $5150 at 8% simple interest for 8 years.

Correct Answer  $8446

Solution & Explanation

Solution

Given,

Principal (P) = $5150

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) = $5150 × 8% × 8

= $5150 ×⁸/₁₀₀ × 8

= ^{5150 × 8 × 8}/₁₀₀

= ^{41200 × 8}/₁₀₀

= ³²⁹⁶⁰⁰/₁₀₀

= $3296

Thus, Simple Interest = $3296

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 = $5150 + $3296

= $8446

Thus, Amount to be paid = $8446 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 = $5150

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

And, Time (t) = 8 years

Thus, Amount (A)

= $5150 + ($5150 × 8% × 8)

= $5150 + ($5150 ×⁸/₁₀₀ × 8)

= $5150 + (^{5150 × 8 × 8}/₁₀₀)

= $5150 + (^{41200 × 8}/₁₀₀)

= $5150 + (³²⁹⁶⁰⁰/₁₀₀)

= $5150 + $3296 = $8446

Thus, Amount (A) to be paid = $8446 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 $5150, the simple interest in 1 year

= ⁸/₁₀₀ × 5150

= ^{8 × 5150}/₁₀₀

= ⁴¹²⁰⁰/₁₀₀ = $412

Thus, simple interest for 1 year = $412

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $412 × 8 = $3296

Thus, Simple Interest (SI) = $3296

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5150 + $3296

= $8446

Thus, Amount to be paid = $8446 Answer

Similar Questions

(1) What amount does Richard have to pay after 5 years if he takes a loan of $3600 at 10% simple interest?

(2) Betty took a loan of $6500 at the rate of 6% simple interest per annum. If he paid an amount of $9230 to clear the loan, then find the time period of the loan.

(3) What amount does Susan have to pay after 5 years if he takes a loan of $3650 at 5% simple interest?

(4) Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 9% simple interest.

(5) How much loan did Jeffrey borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $9360 to clear it?

(6) What amount does Sarah have to pay after 6 years if he takes a loan of $3850 at 5% simple interest?

(7) What amount does Susan have to pay after 5 years if he takes a loan of $3650 at 6% simple interest?

(8) Find the amount to be paid if David borrowed a sum of $5400 at 2% simple interest for 7 years.

(9) How much loan did Kenneth borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8050 to clear it?

(10) If John paid $3840 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.