Simple Interest
Math MCQs

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

Correct Answer  $4256

Solution & Explanation

Solution

Given,

Principal (P) = $3800

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) = $3800 × 3% × 4

= $3800 ׳/₁₀₀ × 4

= ^{3800 × 3 × 4}/₁₀₀

= ^{11400 × 4}/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) = 3%

And, Time (t) = 4 years

Thus, Amount (A)

= $3800 + ($3800 × 3% × 4)

= $3800 + ($3800 ׳/₁₀₀ × 4)

= $3800 + (^{3800 × 3 × 4}/₁₀₀)

= $3800 + (^{11400 × 4}/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 = 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 $3800, the simple interest in 1 year

= ³/₁₀₀ × 3800

= ^{3 × 3800}/₁₀₀

= ¹¹⁴⁰⁰/₁₀₀ = $114

Thus, simple interest for 1 year = $114

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $114 × 4 = $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) David took a loan of $4800 at the rate of 9% simple interest per annum. If he paid an amount of $7824 to clear the loan, then find the time period of the loan.

(2) Calculate the amount due if Sarah borrowed a sum of $3850 at 10% simple interest for 4 years.

(3) If Jessica borrowed $3750 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(4) How much loan did Michael borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $5830 to clear it?

(5) How much loan did Brian borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8280 to clear it?

(6) Mark took a loan of $6800 at the rate of 6% simple interest per annum. If he paid an amount of $9656 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due after 10 years if Michael borrowed a sum of $5300 at a rate of 4% simple interest.

(8) Patricia took a loan of $4300 at the rate of 9% simple interest per annum. If he paid an amount of $7009 to clear the loan, then find the time period of the loan.

(9) Barbara took a loan of $5100 at the rate of 8% simple interest per annum. If he paid an amount of $8772 to clear the loan, then find the time period of the loan.

(10) What amount does James have to pay after 6 years if he takes a loan of $3000 at 5% simple interest?