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) Find the amount to be paid if Barbara borrowed a sum of $5550 at 10% simple interest for 8 years.

(2) Find the amount to be paid if William borrowed a sum of $5500 at 6% simple interest for 8 years.

(3) Mark took a loan of $6800 at the rate of 10% simple interest per annum. If he paid an amount of $12240 to clear the loan, then find the time period of the loan.

(4) Donald had to pay $4905 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(5) What amount does Karen have to pay after 6 years if he takes a loan of $3950 at 8% simple interest?

(6) Calculate the amount due after 10 years if Sarah borrowed a sum of $5850 at a rate of 5% simple interest.

(7) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 2% simple interest for 8 years.

(8) What amount does John have to pay after 6 years if he takes a loan of $3200 at 7% simple interest?

(9) Calculate the amount due if David borrowed a sum of $3400 at 10% simple interest for 4 years.

(10) Elizabeth took a loan of $4900 at the rate of 9% simple interest per annum. If he paid an amount of $8869 to clear the loan, then find the time period of the loan.