Simple Interest
Math MCQs

Question :    Calculate the amount due if Linda borrowed a sum of $3350 at 8% simple interest for 3 years.

Correct Answer  $4154

Solution & Explanation

Solution

Given,

Principal (P) = $3350

Rate of Simple Interest (SI) = 8%

Time (t) = 3 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) = $3350 × 8% × 3

= $3350 ×⁸/₁₀₀ × 3

= ^{3350 × 8 × 3}/₁₀₀

= ^{26800 × 3}/₁₀₀

= ⁸⁰⁴⁰⁰/₁₀₀

= $804

Thus, Simple Interest = $804

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 = $3350 + $804

= $4154

Thus, Amount to be paid = $4154 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 = $3350

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

And, Time (t) = 3 years

Thus, Amount (A)

= $3350 + ($3350 × 8% × 3)

= $3350 + ($3350 ×⁸/₁₀₀ × 3)

= $3350 + (^{3350 × 8 × 3}/₁₀₀)

= $3350 + (^{26800 × 3}/₁₀₀)

= $3350 + (⁸⁰⁴⁰⁰/₁₀₀)

= $3350 + $804 = $4154

Thus, Amount (A) to be paid = $4154 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 $3350, the simple interest in 1 year

= ⁸/₁₀₀ × 3350

= ^{8 × 3350}/₁₀₀

= ²⁶⁸⁰⁰/₁₀₀ = $268

Thus, simple interest for 1 year = $268

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $268 × 3 = $804

Thus, Simple Interest (SI) = $804

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3350 + $804

= $4154

Thus, Amount to be paid = $4154 Answer

Similar Questions

(1) Find the amount to be paid if James borrowed a sum of $5000 at 10% simple interest for 7 years.

(2) Richard had to pay $3816 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(3) What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 5% simple interest?

(4) Find the amount to be paid if Richard borrowed a sum of $5600 at 2% simple interest for 8 years.

(5) Calculate the amount due if Barbara borrowed a sum of $3550 at 6% simple interest for 4 years.

(6) Calculate the amount due after 9 years if Joseph borrowed a sum of $5700 at a rate of 5% simple interest.

(7) What amount will be due after 2 years if James borrowed a sum of $3000 at a 5% simple interest?

(8) Joseph took a loan of $5400 at the rate of 6% simple interest per annum. If he paid an amount of $8316 to clear the loan, then find the time period of the loan.

(9) In how much time a principal of $3000 will amount to $3600 at a simple interest of 5% per annum?

(10) Margaret took a loan of $6700 at the rate of 10% simple interest per annum. If he paid an amount of $10720 to clear the loan, then find the time period of the loan.