Simple Interest
Math MCQs

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

Correct Answer  $10640

Solution & Explanation

Solution

Given,

Principal (P) = $5600

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) = $5600 × 10% × 9

= $5600 ×¹⁰/₁₀₀ × 9

= ^{5600 × 10 × 9}/₁₀₀

= ^{56000 × 9}/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) = 10%

And, Time (t) = 9 years

Thus, Amount (A)

= $5600 + ($5600 × 10% × 9)

= $5600 + ($5600 ×¹⁰/₁₀₀ × 9)

= $5600 + (^{5600 × 10 × 9}/₁₀₀)

= $5600 + (^{56000 × 9}/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 = 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 $5600, the simple interest in 1 year

= ¹⁰/₁₀₀ × 5600

= ^{10 × 5600}/₁₀₀

= ⁵⁶⁰⁰⁰/₁₀₀ = $560

Thus, simple interest for 1 year = $560

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $560 × 9 = $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) Calculate the amount due after 9 years if Karen borrowed a sum of $5950 at a rate of 4% simple interest.

(2) Thomas took a loan of $5600 at the rate of 7% simple interest per annum. If he paid an amount of $9128 to clear the loan, then find the time period of the loan.

(3) What amount does Karen have to pay after 5 years if he takes a loan of $3950 at 4% simple interest?

(4) Christopher took a loan of $6000 at the rate of 6% simple interest per annum. If he paid an amount of $8880 to clear the loan, then find the time period of the loan.

(5) What amount does Elizabeth have to pay after 5 years if he takes a loan of $3450 at 8% simple interest?

(6) What amount does Joseph have to pay after 6 years if he takes a loan of $3700 at 9% simple interest?

(7) Joseph had to pay $4255 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(8) Steven had to pay $5152 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(9) If Karen paid $4740 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(10) Robert took a loan of $4200 at the rate of 8% simple interest per annum. If he paid an amount of $6888 to clear the loan, then find the time period of the loan.