Simple Interest
Math MCQs

Question :    Calculate the amount due if Michael borrowed a sum of $3300 at 6% simple interest for 4 years.

Correct Answer  $4092

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 6%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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 × 6% × 4

= $3300 ×⁶/₁₀₀ × 4

= ^{3300 × 6 × 4}/₁₀₀

= ^{19800 × 4}/₁₀₀

= ⁷⁹²⁰⁰/₁₀₀

= $792

Thus, Simple Interest = $792

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 + $792

= $4092

Thus, Amount to be paid = $4092 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) = 6%

And, Time (t) = 4 years

Thus, Amount (A)

= $3300 + ($3300 × 6% × 4)

= $3300 + ($3300 ×⁶/₁₀₀ × 4)

= $3300 + (^{3300 × 6 × 4}/₁₀₀)

= $3300 + (^{19800 × 4}/₁₀₀)

= $3300 + (⁷⁹²⁰⁰/₁₀₀)

= $3300 + $792 = $4092

Thus, Amount (A) to be paid = $4092 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $3300, the simple interest in 1 year

= ⁶/₁₀₀ × 3300

= ^{6 × 3300}/₁₀₀

= ¹⁹⁸⁰⁰/₁₀₀ = $198

Thus, simple interest for 1 year = $198

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $198 × 4 = $792

Thus, Simple Interest (SI) = $792

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $792

= $4092

Thus, Amount to be paid = $4092 Answer

Similar Questions

(1) Karen took a loan of $5900 at the rate of 6% simple interest per annum. If he paid an amount of $8732 to clear the loan, then find the time period of the loan.

(2) David took a loan of $4800 at the rate of 8% simple interest per annum. If he paid an amount of $7872 to clear the loan, then find the time period of the loan.

(3) If Christopher paid $4320 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(4) Find the amount to be paid if Karen borrowed a sum of $5950 at 4% simple interest for 8 years.

(5) How much loan did Jacob borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $10000 to clear it?

(6) What amount does Elizabeth have to pay after 5 years if he takes a loan of $3450 at 10% simple interest?

(7) Calculate the amount due after 10 years if Susan borrowed a sum of $5650 at a rate of 5% simple interest.

(8) Karen took a loan of $5900 at the rate of 8% simple interest per annum. If he paid an amount of $10620 to clear the loan, then find the time period of the loan.

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

(10) What amount will be due after 2 years if William borrowed a sum of $3250 at a 4% simple interest?