Simple Interest
Math MCQs

Question :    Calculate the amount due if Thomas borrowed a sum of $3800 at 4% simple interest for 3 years.

Correct Answer  $4256

Solution & Explanation

Solution

Given,

Principal (P) = $3800

Rate of Simple Interest (SI) = 4%

Time (t) = 3 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) = $3800 × 4% × 3

= $3800 ×⁴/₁₀₀ × 3

= ^{3800 × 4 × 3}/₁₀₀

= ^{15200 × 3}/₁₀₀

= ⁴⁵⁶⁰⁰/₁₀₀

= $456

Thus, Simple Interest = $456

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 = $3800 + $456

= $4256

Thus, Amount to be paid = $4256 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 = $3800

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

And, Time (t) = 3 years

Thus, Amount (A)

= $3800 + ($3800 × 4% × 3)

= $3800 + ($3800 ×⁴/₁₀₀ × 3)

= $3800 + (^{3800 × 4 × 3}/₁₀₀)

= $3800 + (^{15200 × 3}/₁₀₀)

= $3800 + (⁴⁵⁶⁰⁰/₁₀₀)

= $3800 + $456 = $4256

Thus, Amount (A) to be paid = $4256 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 $3800, the simple interest in 1 year

= ⁴/₁₀₀ × 3800

= ^{4 × 3800}/₁₀₀

= ¹⁵²⁰⁰/₁₀₀ = $152

Thus, simple interest for 1 year = $152

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $152 × 3 = $456

Thus, Simple Interest (SI) = $456

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3800 + $456

= $4256

Thus, Amount to be paid = $4256 Answer

Similar Questions

(1) Christopher had to pay $4480 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(2) Calculate the amount due if Karen borrowed a sum of $3950 at 8% simple interest for 4 years.

(3) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 3% simple interest.

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

(5) Calculate the amount due if William borrowed a sum of $3500 at 6% simple interest for 4 years.

(6) Sarah took a loan of $5700 at the rate of 8% simple interest per annum. If he paid an amount of $9804 to clear the loan, then find the time period of the loan.

(7) Find the amount to be paid if Charles borrowed a sum of $5900 at 4% simple interest for 8 years.

(8) How much loan did Rebecca borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $8415 to clear it?

(9) If Charles borrowed $3900 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(10) Matthew took a loan of $6400 at the rate of 6% simple interest per annum. If he paid an amount of $10240 to clear the loan, then find the time period of the loan.