Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 3% simple interest.

Correct Answer  $7280

Solution & Explanation

Solution

Given,

Principal (P) = $5600

Rate of Simple Interest (SI) = 3%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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) = $5600 × 3% × 10

= $5600 ׳/₁₀₀ × 10

= ^{5600 × 3 × 10}/₁₀₀

= ^{16800 × 10}/₁₀₀

= ¹⁶⁸⁰⁰⁰/₁₀₀

= $1680

Thus, Simple Interest = $1680

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 = $5600 + $1680

= $7280

Thus, Amount to be paid = $7280 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 = $5600

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 10 years

Thus, Amount (A)

= $5600 + ($5600 × 3% × 10)

= $5600 + ($5600 ׳/₁₀₀ × 10)

= $5600 + (^{5600 × 3 × 10}/₁₀₀)

= $5600 + (^{16800 × 10}/₁₀₀)

= $5600 + (¹⁶⁸⁰⁰⁰/₁₀₀)

= $5600 + $1680 = $7280

Thus, Amount (A) to be paid = $7280 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = ³/₁₀₀

∴ For $5600, the simple interest in 1 year

= ³/₁₀₀ × 5600

= ^{3 × 5600}/₁₀₀

= ¹⁶⁸⁰⁰/₁₀₀ = $168

Thus, simple interest for 1 year = $168

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $168 × 10 = $1680

Thus, Simple Interest (SI) = $1680

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5600 + $1680

= $7280

Thus, Amount to be paid = $7280 Answer

Similar Questions

(1) If Donna paid $5432 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(2) Linda took a loan of $4700 at the rate of 6% simple interest per annum. If he paid an amount of $6956 to clear the loan, then find the time period of the loan.

(3) If Nancy paid $4482 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(4) Calculate the amount due if Mary borrowed a sum of $3050 at 10% simple interest for 4 years.

(5) Barbara took a loan of $5100 at the rate of 8% simple interest per annum. If he paid an amount of $8364 to clear the loan, then find the time period of the loan.

(6) In how much time a principal of $3200 will amount to $3392 at a simple interest of 2% per annum?

(7) Sarah took a loan of $5700 at the rate of 9% simple interest per annum. If he paid an amount of $8778 to clear the loan, then find the time period of the loan.

(8) Daniel took a loan of $6200 at the rate of 9% simple interest per annum. If he paid an amount of $11222 to clear the loan, then find the time period of the loan.

(9) How much loan did Carol borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8107.5 to clear it?

(10) Margaret took a loan of $6700 at the rate of 8% simple interest per annum. If he paid an amount of $9916 to clear the loan, then find the time period of the loan.