Simple Interest
Math MCQs

Question :    Calculate the amount due if Mary borrowed a sum of $3050 at 4% simple interest for 4 years.

Correct Answer  $3538

Solution & Explanation

Solution

Given,

Principal (P) = $3050

Rate of Simple Interest (SI) = 4%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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) = $3050 × 4% × 4

= $3050 ×⁴/₁₀₀ × 4

= ^{3050 × 4 × 4}/₁₀₀

= ^{12200 × 4}/₁₀₀

= ⁴⁸⁸⁰⁰/₁₀₀

= $488

Thus, Simple Interest = $488

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 = $3050 + $488

= $3538

Thus, Amount to be paid = $3538 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 = $3050

Rate of Simple Interest (SI) or (R) = 4%

And, Time (t) = 4 years

Thus, Amount (A)

= $3050 + ($3050 × 4% × 4)

= $3050 + ($3050 ×⁴/₁₀₀ × 4)

= $3050 + (^{3050 × 4 × 4}/₁₀₀)

= $3050 + (^{12200 × 4}/₁₀₀)

= $3050 + (⁴⁸⁸⁰⁰/₁₀₀)

= $3050 + $488 = $3538

Thus, Amount (A) to be paid = $3538 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $3050, the simple interest in 1 year

= ⁴/₁₀₀ × 3050

= ^{4 × 3050}/₁₀₀

= ¹²²⁰⁰/₁₀₀ = $122

Thus, simple interest for 1 year = $122

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $122 × 4 = $488

Thus, Simple Interest (SI) = $488

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3050 + $488

= $3538

Thus, Amount to be paid = $3538 Answer

Similar Questions

(1) If Mark paid $4752 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(2) Lisa took a loan of $6100 at the rate of 7% simple interest per annum. If he paid an amount of $9516 to clear the loan, then find the time period of the loan.

(3) What amount does Thomas have to pay after 5 years if he takes a loan of $3800 at 9% simple interest?

(4) What amount does Christopher have to pay after 6 years if he takes a loan of $4000 at 2% simple interest?

(5) Find the amount to be paid if Barbara borrowed a sum of $5550 at 5% simple interest for 7 years.

(6) James took a loan of $4000 at the rate of 6% simple interest per annum. If he paid an amount of $6160 to clear the loan, then find the time period of the loan.

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

(8) Find the amount to be paid if Jessica borrowed a sum of $5750 at 5% simple interest for 7 years.

(9) If Anthony paid $5160 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(10) Find the amount to be paid if John borrowed a sum of $5200 at 10% simple interest for 8 years.