Simple Interest
Math MCQs

Question :  ( 1 of 10 )  Calculate the amount due if Michael borrowed a sum of $3300 at 10% simple interest for 3 years.

Correct Answer  $4290

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 10%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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) = $3300 × 10% × 3

= $3300 ×¹⁰/₁₀₀ × 3

= ^{3300 × 10 × 3}/₁₀₀

= ^{33000 × 3}/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 = $3300 + $990

= $4290

Thus, Amount to be paid = $4290 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 = $3300

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 3 years

Thus, Amount (A)

= $3300 + ($3300 × 10% × 3)

= $3300 + ($3300 ×¹⁰/₁₀₀ × 3)

= $3300 + (^{3300 × 10 × 3}/₁₀₀)

= $3300 + (^{33000 × 3}/₁₀₀)

= $3300 + (⁹⁹⁰⁰⁰/₁₀₀)

= $3300 + $990 = $4290

Thus, Amount (A) to be paid = $4290 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = ¹⁰/₁₀₀

∴ For $3300, the simple interest in 1 year

= ¹⁰/₁₀₀ × 3300

= ^{10 × 3300}/₁₀₀

= ³³⁰⁰⁰/₁₀₀ = $330

Thus, simple interest for 1 year = $330

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $330 × 3 = $990

Thus, Simple Interest (SI) = $990

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $990

= $4290

Thus, Amount to be paid = $4290 Answer

Similar Questions

(1) What amount does Karen have to pay after 5 years if he takes a loan of $3950 at 5% simple interest?

(2) What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 8% simple interest?

(3) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 4% simple interest.

(4) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 8% simple interest?

(5) Margaret took a loan of $6700 at the rate of 8% simple interest per annum. If he paid an amount of $12060 to clear the loan, then find the time period of the loan.

(6) Find the amount to be paid if Mary borrowed a sum of $5050 at 3% simple interest for 7 years.

(7) What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 7% simple interest?

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

(9) John took a loan of $4400 at the rate of 9% simple interest per annum. If he paid an amount of $7964 to clear the loan, then find the time period of the loan.

(10) Barbara took a loan of $5100 at the rate of 9% simple interest per annum. If he paid an amount of $8313 to clear the loan, then find the time period of the loan.