Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 9% simple interest.

Correct Answer  $10640

Solution & Explanation

Solution

Given,

Principal (P) = $5600

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) = $5600 × 9% × 10

= $5600 ×⁹/₁₀₀ × 10

= ^{5600 × 9 × 10}/₁₀₀

= ^{50400 × 10}/₁₀₀

= ⁵⁰⁴⁰⁰⁰/₁₀₀

= $5040

Thus, Simple Interest = $5040

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 + $5040

= $10640

Thus, Amount to be paid = $10640 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) = 9%

And, Time (t) = 10 years

Thus, Amount (A)

= $5600 + ($5600 × 9% × 10)

= $5600 + ($5600 ×⁹/₁₀₀ × 10)

= $5600 + (^{5600 × 9 × 10}/₁₀₀)

= $5600 + (^{50400 × 10}/₁₀₀)

= $5600 + (⁵⁰⁴⁰⁰⁰/₁₀₀)

= $5600 + $5040 = $10640

Thus, Amount (A) to be paid = $10640 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 $5600, the simple interest in 1 year

= ⁹/₁₀₀ × 5600

= ^{9 × 5600}/₁₀₀

= ⁵⁰⁴⁰⁰/₁₀₀ = $504

Thus, simple interest for 1 year = $504

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $504 × 10 = $5040

Thus, Simple Interest (SI) = $5040

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5600 + $5040

= $10640

Thus, Amount to be paid = $10640 Answer

Similar Questions

(1) If Lisa paid $4860 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(2) What amount does Jessica have to pay after 6 years if he takes a loan of $3750 at 9% simple interest?

(3) What amount does Mary have to pay after 5 years if he takes a loan of $3050 at 6% simple interest?

(4) Calculate the amount due after 10 years if Jessica borrowed a sum of $5750 at a rate of 3% simple interest.

(5) Susan took a loan of $5300 at the rate of 6% simple interest per annum. If he paid an amount of $8480 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if David borrowed a sum of $3400 at 10% simple interest for 3 years.

(7) In how much time a principal of $3000 will amount to $3240 at a simple interest of 2% per annum?

(8) What amount will be due after 2 years if Richard borrowed a sum of $3300 at a 6% simple interest?

(9) What amount does Thomas have to pay after 6 years if he takes a loan of $3800 at 7% simple interest?

(10) What amount does Jessica have to pay after 6 years if he takes a loan of $3750 at 4% simple interest?