Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 4% simple interest.

Correct Answer  $7888

Solution & Explanation

Solution

Given,

Principal (P) = $5800

Rate of Simple Interest (SI) = 4%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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) = $5800 × 4% × 9

= $5800 ×⁴/₁₀₀ × 9

= ^{5800 × 4 × 9}/₁₀₀

= ^{23200 × 9}/₁₀₀

= ²⁰⁸⁸⁰⁰/₁₀₀

= $2088

Thus, Simple Interest = $2088

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 = $5800 + $2088

= $7888

Thus, Amount to be paid = $7888 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 = $5800

Rate of Simple Interest (SI) or (R) = 4%

And, Time (t) = 9 years

Thus, Amount (A)

= $5800 + ($5800 × 4% × 9)

= $5800 + ($5800 ×⁴/₁₀₀ × 9)

= $5800 + (^{5800 × 4 × 9}/₁₀₀)

= $5800 + (^{23200 × 9}/₁₀₀)

= $5800 + (²⁰⁸⁸⁰⁰/₁₀₀)

= $5800 + $2088 = $7888

Thus, Amount (A) to be paid = $7888 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $5800, the simple interest in 1 year

= ⁴/₁₀₀ × 5800

= ^{4 × 5800}/₁₀₀

= ²³²⁰⁰/₁₀₀ = $232

Thus, simple interest for 1 year = $232

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $232 × 9 = $2088

Thus, Simple Interest (SI) = $2088

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5800 + $2088

= $7888

Thus, Amount to be paid = $7888 Answer

Similar Questions

(1) Robert took a loan of $4200 at the rate of 6% simple interest per annum. If he paid an amount of $5964 to clear the loan, then find the time period of the loan.

(2) Lisa took a loan of $6100 at the rate of 6% simple interest per annum. If he paid an amount of $8296 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 3% simple interest.

(4) Calculate the amount due after 10 years if Charles borrowed a sum of $5900 at a rate of 2% simple interest.

(5) Calculate the amount due after 9 years if Charles borrowed a sum of $5900 at a rate of 6% simple interest.

(6) Linda took a loan of $4700 at the rate of 9% simple interest per annum. If he paid an amount of $8507 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due if Joseph borrowed a sum of $3700 at 9% simple interest for 4 years.

(8) Calculate the amount due after 9 years if Linda borrowed a sum of $5350 at a rate of 5% simple interest.

(9) Calculate the amount due if Jessica borrowed a sum of $3750 at 7% simple interest for 4 years.

(10) How much loan did Karen borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $6842.5 to clear it?