Simple Interest
Math MCQs

Question :    Calculate the amount due if Thomas borrowed a sum of $3800 at 7% simple interest for 3 years.

Correct Answer  $4598

Solution & Explanation

Solution

Given,

Principal (P) = $3800

Rate of Simple Interest (SI) = 7%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 7% simple interest means, Rate of Simple Interest (SI) is 7% 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 × 7% × 3

= $3800 ×⁷/₁₀₀ × 3

= ^{3800 × 7 × 3}/₁₀₀

= ^{26600 × 3}/₁₀₀

= ⁷⁹⁸⁰⁰/₁₀₀

= $798

Thus, Simple Interest = $798

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 + $798

= $4598

Thus, Amount to be paid = $4598 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) = 7%

And, Time (t) = 3 years

Thus, Amount (A)

= $3800 + ($3800 × 7% × 3)

= $3800 + ($3800 ×⁷/₁₀₀ × 3)

= $3800 + (^{3800 × 7 × 3}/₁₀₀)

= $3800 + (^{26600 × 3}/₁₀₀)

= $3800 + (⁷⁹⁸⁰⁰/₁₀₀)

= $3800 + $798 = $4598

Thus, Amount (A) to be paid = $4598 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 7%

This, means, $7 per $100 per year

∵ For $100, the simple interest for 1 year = $7

∴ For $1, the simple interest for 1 year = ⁷/₁₀₀

∴ For $3800, the simple interest in 1 year

= ⁷/₁₀₀ × 3800

= ^{7 × 3800}/₁₀₀

= ²⁶⁶⁰⁰/₁₀₀ = $266

Thus, simple interest for 1 year = $266

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $266 × 3 = $798

Thus, Simple Interest (SI) = $798

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3800 + $798

= $4598

Thus, Amount to be paid = $4598 Answer

Similar Questions

(1) Betty took a loan of $6500 at the rate of 6% simple interest per annum. If he paid an amount of $10010 to clear the loan, then find the time period of the loan.

(2) If Richard borrowed $3600 from a bank at a rate of 2% simple interest per annum then find the amount to be paid after 2 years.

(3) Susan took a loan of $5300 at the rate of 6% simple interest per annum. If he paid an amount of $7208 to clear the loan, then find the time period of the loan.

(4) James took a loan of $4000 at the rate of 9% simple interest per annum. If he paid an amount of $7600 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 2% simple interest for 4 years.

(6) Linda took a loan of $4700 at the rate of 10% simple interest per annum. If he paid an amount of $8930 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due if Michael borrowed a sum of $3300 at 5% simple interest for 3 years.

(8) Mark had to pay $4664 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(9) Susan took a loan of $5300 at the rate of 10% simple interest per annum. If he paid an amount of $9010 to clear the loan, then find the time period of the loan.

(10) Find the amount to be paid if Christopher borrowed a sum of $6000 at 4% simple interest for 8 years.