Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Charles borrowed a sum of $5900 at a rate of 10% simple interest.

Correct Answer  $11210

Solution & Explanation

Solution

Given,

Principal (P) = $5900

Rate of Simple Interest (SI) = 10%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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) = $5900 × 10% × 9

= $5900 ×¹⁰/₁₀₀ × 9

= ^{5900 × 10 × 9}/₁₀₀

= ^{59000 × 9}/₁₀₀

= ⁵³¹⁰⁰⁰/₁₀₀

= $5310

Thus, Simple Interest = $5310

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 = $5900 + $5310

= $11210

Thus, Amount to be paid = $11210 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 = $5900

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 9 years

Thus, Amount (A)

= $5900 + ($5900 × 10% × 9)

= $5900 + ($5900 ×¹⁰/₁₀₀ × 9)

= $5900 + (^{5900 × 10 × 9}/₁₀₀)

= $5900 + (^{59000 × 9}/₁₀₀)

= $5900 + (⁵³¹⁰⁰⁰/₁₀₀)

= $5900 + $5310 = $11210

Thus, Amount (A) to be paid = $11210 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = ¹⁰/₁₀₀

∴ For $5900, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5900

= ^{10 × 5900}/₁₀₀

= ⁵⁹⁰⁰⁰/₁₀₀ = $590

Thus, simple interest for 1 year = $590

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $590 × 9 = $5310

Thus, Simple Interest (SI) = $5310

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5900 + $5310

= $11210

Thus, Amount to be paid = $11210 Answer

Similar Questions

(1) Calculate the amount due if Susan borrowed a sum of $3650 at 8% simple interest for 4 years.

(2) Betty had to pay $4760 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(3) Calculate the amount due if Joseph borrowed a sum of $3700 at 6% simple interest for 4 years.

(4) Karen took a loan of $5900 at the rate of 8% simple interest per annum. If he paid an amount of $9204 to clear the loan, then find the time period of the loan.

(5) In how much time a principal of $3100 will amount to $3224 at a simple interest of 2% per annum?

(6) Calculate the amount due after 9 years if Charles borrowed a sum of $5900 at a rate of 7% simple interest.

(7) If Christopher borrowed $4000 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(8) Calculate the amount due after 10 years if Thomas borrowed a sum of $5800 at a rate of 4% simple interest.

(9) Calculate the amount due if John borrowed a sum of $3200 at 2% simple interest for 4 years.

(10) Calculate the amount due if Mary borrowed a sum of $3050 at 9% simple interest for 4 years.