Simple Interest
Math MCQs

Question :    Calculate the amount due if Linda borrowed a sum of $3350 at 3% simple interest for 4 years.

Correct Answer  $3752

Solution & Explanation

Solution

Given,

Principal (P) = $3350

Rate of Simple Interest (SI) = 3%

Time (t) = 4 years

Thus, Amount (A) = ?

The Rate of Interest is always calculated per annum, i.e. per year.

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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 × 3% × 4

= $3350 ׳/₁₀₀ × 4

= ^{3350 × 3 × 4}/₁₀₀

= ^{10050 × 4}/₁₀₀

= ⁴⁰²⁰⁰/₁₀₀

= $402

Thus, Simple Interest = $402

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 + $402

= $3752

Thus, Amount to be paid = $3752 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) = 3%

And, Time (t) = 4 years

Thus, Amount (A)

= $3350 + ($3350 × 3% × 4)

= $3350 + ($3350 ׳/₁₀₀ × 4)

= $3350 + (^{3350 × 3 × 4}/₁₀₀)

= $3350 + (^{10050 × 4}/₁₀₀)

= $3350 + (⁴⁰²⁰⁰/₁₀₀)

= $3350 + $402 = $3752

Thus, Amount (A) to be paid = $3752 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = ³/₁₀₀

∴ For $3350, the simple interest in 1 year

= ³/₁₀₀ × 3350

= ^{3 × 3350}/₁₀₀

= ¹⁰⁰⁵⁰/₁₀₀ = $100.5

Thus, simple interest for 1 year = $100.5

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $100.5 × 4 = $402

Thus, Simple Interest (SI) = $402

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3350 + $402

= $3752

Thus, Amount to be paid = $3752 Answer

Similar Questions

(1) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 2% simple interest.

(2) Lisa had to pay $4657.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(3) How much loan did Elizabeth borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $5995 to clear it?

(4) If William paid $4060 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(5) Calculate the amount due if Sarah borrowed a sum of $3850 at 5% simple interest for 4 years.

(6) What amount does Michael have to pay after 5 years if he takes a loan of $3300 at 10% simple interest?

(7) Calculate the amount due if Robert borrowed a sum of $3100 at 8% simple interest for 3 years.

(8) Robert took a loan of $4200 at the rate of 8% simple interest per annum. If he paid an amount of $7560 to clear the loan, then find the time period of the loan.

(9) What amount does James have to pay after 5 years if he takes a loan of $3000 at 7% simple interest?

(10) What amount does Richard have to pay after 6 years if he takes a loan of $3600 at 4% simple interest?