Simple Interest
Math MCQs

Question :    What amount does Michael have to pay after 6 years if he takes a loan of $3300 at 5% simple interest?

Correct Answer  $4290

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 5%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 5% simple interest means, Rate of Simple Interest (SI) is 5% 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 × 5% × 6

= $3300 ×⁵/₁₀₀ × 6

= ^{3300 × 5 × 6}/₁₀₀

= ^{16500 × 6}/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) = 5%

And, Time (t) = 6 years

Thus, Amount (A)

= $3300 + ($3300 × 5% × 6)

= $3300 + ($3300 ×⁵/₁₀₀ × 6)

= $3300 + (^{3300 × 5 × 6}/₁₀₀)

= $3300 + (^{16500 × 6}/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 = 5%

This, means, $5 per $100 per year

∵ For $100, the simple interest for 1 year = $5

∴ For $1, the simple interest for 1 year = ⁵/₁₀₀

∴ For $3300, the simple interest in 1 year

= ⁵/₁₀₀ × 3300

= ^{5 × 3300}/₁₀₀

= ¹⁶⁵⁰⁰/₁₀₀ = $165

Thus, simple interest for 1 year = $165

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $165 × 6 = $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) Mark took a loan of $6800 at the rate of 9% simple interest per annum. If he paid an amount of $12308 to clear the loan, then find the time period of the loan.

(2) If James paid $3360 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(3) What amount does Jessica have to pay after 5 years if he takes a loan of $3750 at 2% simple interest?

(4) How much loan did Timothy borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8510 to clear it?

(5) Betty had to pay $4887.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(6) Find the amount to be paid if Richard borrowed a sum of $5600 at 9% simple interest for 8 years.

(7) Anthony took a loan of $6600 at the rate of 10% simple interest per annum. If he paid an amount of $12540 to clear the loan, then find the time period of the loan.

(8) Calculate the amount due if Susan borrowed a sum of $3650 at 9% simple interest for 3 years.

(9) Find the amount to be paid if Michael borrowed a sum of $5300 at 2% simple interest for 8 years.

(10) Find the amount to be paid if Barbara borrowed a sum of $5550 at 7% simple interest for 7 years.