Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if William borrowed a sum of $5500 at a rate of 2% simple interest.

Correct Answer  $6490

Solution & Explanation

Solution

Given,

Principal (P) = $5500

Rate of Simple Interest (SI) = 2%

Time (t) = 9 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) = $5500 × 2% × 9

= $5500 ײ/₁₀₀ × 9

= ^{5500 × 2 × 9}/₁₀₀

= ^{11000 × 9}/₁₀₀

= ⁹⁹⁰⁰⁰/₁₀₀

= $990

Thus, Simple Interest = $990

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 = $5500 + $990

= $6490

Thus, Amount to be paid = $6490 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 = $5500

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

And, Time (t) = 9 years

Thus, Amount (A)

= $5500 + ($5500 × 2% × 9)

= $5500 + ($5500 ײ/₁₀₀ × 9)

= $5500 + (^{5500 × 2 × 9}/₁₀₀)

= $5500 + (^{11000 × 9}/₁₀₀)

= $5500 + (⁹⁹⁰⁰⁰/₁₀₀)

= $5500 + $990 = $6490

Thus, Amount (A) to be paid = $6490 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 $5500, the simple interest in 1 year

= ²/₁₀₀ × 5500

= ^{2 × 5500}/₁₀₀

= ¹¹⁰⁰⁰/₁₀₀ = $110

Thus, simple interest for 1 year = $110

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $110 × 9 = $990

Thus, Simple Interest (SI) = $990

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5500 + $990

= $6490

Thus, Amount to be paid = $6490 Answer

Similar Questions

(1) Calculate the amount due if Robert borrowed a sum of $3100 at 3% simple interest for 4 years.

(2) Find the amount to be paid if Joseph borrowed a sum of $5700 at 4% simple interest for 7 years.

(3) Find the amount to be paid if Susan borrowed a sum of $5650 at 2% simple interest for 8 years.

(4) In how much time a principal of $3150 will amount to $3654 at a simple interest of 4% per annum?

(5) Daniel took a loan of $6200 at the rate of 6% simple interest per annum. If he paid an amount of $9548 to clear the loan, then find the time period of the loan.

(6) Elizabeth took a loan of $4900 at the rate of 7% simple interest per annum. If he paid an amount of $6958 to clear the loan, then find the time period of the loan.

(7) Matthew took a loan of $6400 at the rate of 7% simple interest per annum. If he paid an amount of $9984 to clear the loan, then find the time period of the loan.

(8) Karen took a loan of $5900 at the rate of 8% simple interest per annum. If he paid an amount of $9204 to clear the loan, then find the time period of the loan.

(9) How much loan did Carol borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $7755 to clear it?

(10) Lisa took a loan of $6100 at the rate of 9% simple interest per annum. If he paid an amount of $11041 to clear the loan, then find the time period of the loan.