Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Karen borrowed a sum of $5950 at a rate of 9% simple interest.

Correct Answer  $11305

Solution & Explanation

Solution

Given,

Principal (P) = $5950

Rate of Simple Interest (SI) = 9%

Time (t) = 10 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) = $5950 × 9% × 10

= $5950 ×⁹/₁₀₀ × 10

= ^{5950 × 9 × 10}/₁₀₀

= ^{53550 × 10}/₁₀₀

= ⁵³⁵⁵⁰⁰/₁₀₀

= $5355

Thus, Simple Interest = $5355

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 = $5950 + $5355

= $11305

Thus, Amount to be paid = $11305 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 = $5950

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

And, Time (t) = 10 years

Thus, Amount (A)

= $5950 + ($5950 × 9% × 10)

= $5950 + ($5950 ×⁹/₁₀₀ × 10)

= $5950 + (^{5950 × 9 × 10}/₁₀₀)

= $5950 + (^{53550 × 10}/₁₀₀)

= $5950 + (⁵³⁵⁵⁰⁰/₁₀₀)

= $5950 + $5355 = $11305

Thus, Amount (A) to be paid = $11305 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 $5950, the simple interest in 1 year

= ⁹/₁₀₀ × 5950

= ^{9 × 5950}/₁₀₀

= ⁵³⁵⁵⁰/₁₀₀ = $535.5

Thus, simple interest for 1 year = $535.5

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $535.5 × 10 = $5355

Thus, Simple Interest (SI) = $5355

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5950 + $5355

= $11305

Thus, Amount to be paid = $11305 Answer

Similar Questions

(1) Calculate the amount due if James borrowed a sum of $3000 at 6% simple interest for 3 years.

(2) Calculate the amount due if Richard borrowed a sum of $3600 at 6% simple interest for 4 years.

(3) Calculate the amount due if Michael borrowed a sum of $3300 at 4% simple interest for 4 years.

(4) What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 3% simple interest?

(5) Find the amount to be paid if Barbara borrowed a sum of $5550 at 2% simple interest for 7 years.

(6) In how much time a principal of $3100 will amount to $3348 at a simple interest of 4% per annum?

(7) If Elizabeth paid $4140 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(8) Calculate the amount due if Elizabeth borrowed a sum of $3450 at 2% simple interest for 4 years.

(9) Calculate the amount due if James borrowed a sum of $3000 at 7% simple interest for 4 years.

(10) Calculate the amount due if Joseph borrowed a sum of $3700 at 9% simple interest for 3 years.