Simple Interest
Math MCQs

Question :    Find the amount to be paid if Susan borrowed a sum of $5650 at 2% simple interest for 7 years.

Correct Answer  $6441

Solution & Explanation

Solution

Given,

Principal (P) = $5650

Rate of Simple Interest (SI) = 2%

Time (t) = 7 years

Thus, Amount (A) = ?

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

Thus, here 2% simple interest means, Rate of Simple Interest (SI) is 2% 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) = $5650 × 2% × 7

= $5650 ײ/₁₀₀ × 7

= ^{5650 × 2 × 7}/₁₀₀

= ^{11300 × 7}/₁₀₀

= ⁷⁹¹⁰⁰/₁₀₀

= $791

Thus, Simple Interest = $791

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 = $5650 + $791

= $6441

Thus, Amount to be paid = $6441 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 = $5650

Rate of Simple Interest (SI) or (R) = 2%

And, Time (t) = 7 years

Thus, Amount (A)

= $5650 + ($5650 × 2% × 7)

= $5650 + ($5650 ײ/₁₀₀ × 7)

= $5650 + (^{5650 × 2 × 7}/₁₀₀)

= $5650 + (^{11300 × 7}/₁₀₀)

= $5650 + (⁷⁹¹⁰⁰/₁₀₀)

= $5650 + $791 = $6441

Thus, Amount (A) to be paid = $6441 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 2%

This, means, $2 per $100 per year

∵ For $100, the simple interest for 1 year = $2

∴ For $1, the simple interest for 1 year = ²/₁₀₀

∴ For $5650, the simple interest in 1 year

= ²/₁₀₀ × 5650

= ^{2 × 5650}/₁₀₀

= ¹¹³⁰⁰/₁₀₀ = $113

Thus, simple interest for 1 year = $113

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $113 × 7 = $791

Thus, Simple Interest (SI) = $791

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5650 + $791

= $6441

Thus, Amount to be paid = $6441 Answer

Similar Questions

(1) Christopher took a loan of $6000 at the rate of 6% simple interest per annum. If he paid an amount of $8880 to clear the loan, then find the time period of the loan.

(2) Linda took a loan of $4700 at the rate of 7% simple interest per annum. If he paid an amount of $7003 to clear the loan, then find the time period of the loan.

(3) How much loan did Paul borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $8040 to clear it?

(4) Jessica took a loan of $5500 at the rate of 9% simple interest per annum. If he paid an amount of $9955 to clear the loan, then find the time period of the loan.

(5) Find the amount to be paid if Jessica borrowed a sum of $5750 at 10% simple interest for 7 years.

(6) Michael took a loan of $4600 at the rate of 10% simple interest per annum. If he paid an amount of $7820 to clear the loan, then find the time period of the loan.

(7) Karen took a loan of $5900 at the rate of 8% simple interest per annum. If he paid an amount of $10148 to clear the loan, then find the time period of the loan.

(8) James took a loan of $4000 at the rate of 7% simple interest per annum. If he paid an amount of $5680 to clear the loan, then find the time period of the loan.

(9) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $7980 to clear the loan, then find the time period of the loan.

(10) William took a loan of $5000 at the rate of 7% simple interest per annum. If he paid an amount of $8150 to clear the loan, then find the time period of the loan.