Simple Interest
Math MCQs

Question :    What amount does Michael have to pay after 5 years if he takes a loan of $3300 at 9% simple interest?

Correct Answer  $4785

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 9%

Time (t) = 5 years

Thus, Amount (A) = ?

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

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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 × 9% × 5

= $3300 ×⁹/₁₀₀ × 5

= ^{3300 × 9 × 5}/₁₀₀

= ^{29700 × 5}/₁₀₀

= ¹⁴⁸⁵⁰⁰/₁₀₀

= $1485

Thus, Simple Interest = $1485

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 + $1485

= $4785

Thus, Amount to be paid = $4785 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) = 9%

And, Time (t) = 5 years

Thus, Amount (A)

= $3300 + ($3300 × 9% × 5)

= $3300 + ($3300 ×⁹/₁₀₀ × 5)

= $3300 + (^{3300 × 9 × 5}/₁₀₀)

= $3300 + (^{29700 × 5}/₁₀₀)

= $3300 + (¹⁴⁸⁵⁰⁰/₁₀₀)

= $3300 + $1485 = $4785

Thus, Amount (A) to be paid = $4785 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = ⁹/₁₀₀

∴ For $3300, the simple interest in 1 year

= ⁹/₁₀₀ × 3300

= ^{9 × 3300}/₁₀₀

= ²⁹⁷⁰⁰/₁₀₀ = $297

Thus, simple interest for 1 year = $297

Therefore, simple interest for 5 years

= Simple interest for 1 year × 5

= $297 × 5 = $1485

Thus, Simple Interest (SI) = $1485

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $1485

= $4785

Thus, Amount to be paid = $4785 Answer

Similar Questions

(1) What amount does Joseph have to pay after 5 years if he takes a loan of $3700 at 3% simple interest?

(2) Calculate the amount due if Charles borrowed a sum of $3900 at 2% simple interest for 4 years.

(3) Mary took a loan of $4100 at the rate of 6% simple interest per annum. If he paid an amount of $6314 to clear the loan, then find the time period of the loan.

(4) Thomas took a loan of $5600 at the rate of 10% simple interest per annum. If he paid an amount of $10640 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 8% simple interest.

(6) In how much time a principal of $3000 will amount to $3750 at a simple interest of 5% per annum?

(7) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 3% simple interest?

(8) How much loan did Laura borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $9027.5 to clear it?

(9) Anthony took a loan of $6600 at the rate of 6% simple interest per annum. If he paid an amount of $9768 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due if Joseph borrowed a sum of $3700 at 3% simple interest for 4 years.