Simple Interest
Math MCQs

Question :    Calculate the amount due if Linda borrowed a sum of $3350 at 8% simple interest for 4 years.

Correct Answer  $4422

Solution & Explanation

Solution

Given,

Principal (P) = $3350

Rate of Simple Interest (SI) = 8%

Time (t) = 4 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% × 4

= $3350 ×⁸/₁₀₀ × 4

= ^{3350 × 8 × 4}/₁₀₀

= ^{26800 × 4}/₁₀₀

= ¹⁰⁷²⁰⁰/₁₀₀

= $1072

Thus, Simple Interest = $1072

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 + $1072

= $4422

Thus, Amount to be paid = $4422 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) = 4 years

Thus, Amount (A)

= $3350 + ($3350 × 8% × 4)

= $3350 + ($3350 ×⁸/₁₀₀ × 4)

= $3350 + (^{3350 × 8 × 4}/₁₀₀)

= $3350 + (^{26800 × 4}/₁₀₀)

= $3350 + (¹⁰⁷²⁰⁰/₁₀₀)

= $3350 + $1072 = $4422

Thus, Amount (A) to be paid = $4422 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 4 years

= Simple interest for 1 year × 4

= $268 × 4 = $1072

Thus, Simple Interest (SI) = $1072

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3350 + $1072

= $4422

Thus, Amount to be paid = $4422 Answer

Similar Questions

(1) Find the amount to be paid if Mary borrowed a sum of $5050 at 4% simple interest for 8 years.

(2) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 2% simple interest.

(3) What amount does Joseph have to pay after 5 years if he takes a loan of $3700 at 8% simple interest?

(4) Mark took a loan of $6800 at the rate of 8% simple interest per annum. If he paid an amount of $11152 to clear the loan, then find the time period of the loan.

(5) What amount does Elizabeth have to pay after 6 years if he takes a loan of $3450 at 9% simple interest?

(6) If Barbara paid $4260 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(7) David had to pay $3808 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(8) What amount does Richard have to pay after 6 years if he takes a loan of $3600 at 5% simple interest?

(9) How much loan did Jeffrey borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $9750 to clear it?

(10) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 3% simple interest?