Simple Interest
Math MCQs

Question :    What amount will be due after 2 years if David borrowed a sum of $3200 at a 9% simple interest?

Correct Answer  $3776

Solution & Explanation

Solution

Given,

Principal (P) = $3200

Rate of Simple Interest (SI) = 9%

Time (t) = 2 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) = $3200 × 9% × 2

= $3200 ×⁹/₁₀₀ × 2

= ^{3200 × 9 × 2}/₁₀₀

= ^{28800 × 2}/₁₀₀

= ⁵⁷⁶⁰⁰/₁₀₀

= $576

Thus, Simple Interest = $576

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 = $3200 + $576

= $3776

Thus, Amount to be paid = $3776 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 = $3200

Rate of Simple Interest (SI) or (R) = 9%

And, Time (t) = 2 years

Thus, Amount (A)

= $3200 + ($3200 × 9% × 2)

= $3200 + ($3200 ×⁹/₁₀₀ × 2)

= $3200 + (^{3200 × 9 × 2}/₁₀₀)

= $3200 + (^{28800 × 2}/₁₀₀)

= $3200 + (⁵⁷⁶⁰⁰/₁₀₀)

= $3200 + $576 = $3776

Thus, Amount (A) to be paid = $3776 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 $3200, the simple interest in 1 year

= ⁹/₁₀₀ × 3200

= ^{9 × 3200}/₁₀₀

= ²⁸⁸⁰⁰/₁₀₀ = $288

Thus, simple interest for 1 year = $288

Therefore, simple interest for 2 years

= Simple interest for 1 year × 2

= $288 × 2 = $576

Thus, Simple Interest (SI) = $576

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3200 + $576

= $3776

Thus, Amount to be paid = $3776 Answer

Similar Questions

(1) How much loan did Nancy borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7072.5 to clear it?

(2) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 10% simple interest for 7 years.

(3) What amount will be due after 2 years if Kenneth borrowed a sum of $4000 at a 10% simple interest?

(4) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 5% simple interest.

(5) Margaret took a loan of $6700 at the rate of 10% simple interest per annum. If he paid an amount of $12060 to clear the loan, then find the time period of the loan.

(6) What amount does Karen have to pay after 5 years if he takes a loan of $3950 at 2% simple interest?

(7) Susan took a loan of $5300 at the rate of 6% simple interest per annum. If he paid an amount of $7844 to clear the loan, then find the time period of the loan.

(8) What amount will be due after 2 years if David borrowed a sum of $3200 at a 8% simple interest?

(9) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $7224 to clear the loan, then find the time period of the loan.

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