Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Richard borrowed a sum of $5600 at a rate of 5% simple interest.

Correct Answer  $8400

Solution & Explanation

Solution

Given,

Principal (P) = $5600

Rate of Simple Interest (SI) = 5%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 5% simple interest means, Rate of Simple Interest (SI) is 5% 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 × 5% × 10

= $5600 ×⁵/₁₀₀ × 10

= ^{5600 × 5 × 10}/₁₀₀

= ^{28000 × 10}/₁₀₀

= ²⁸⁰⁰⁰⁰/₁₀₀

= $2800

Thus, Simple Interest = $2800

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 + $2800

= $8400

Thus, Amount to be paid = $8400 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) = 5%

And, Time (t) = 10 years

Thus, Amount (A)

= $5600 + ($5600 × 5% × 10)

= $5600 + ($5600 ×⁵/₁₀₀ × 10)

= $5600 + (^{5600 × 5 × 10}/₁₀₀)

= $5600 + (^{28000 × 10}/₁₀₀)

= $5600 + (²⁸⁰⁰⁰⁰/₁₀₀)

= $5600 + $2800 = $8400

Thus, Amount (A) to be paid = $8400 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 5%

This, means, $5 per $100 per year

∵ For $100, the simple interest for 1 year = $5

∴ For $1, the simple interest for 1 year = ⁵/₁₀₀

∴ For $5600, the simple interest in 1 year

= ⁵/₁₀₀ × 5600

= ^{5 × 5600}/₁₀₀

= ²⁸⁰⁰⁰/₁₀₀ = $280

Thus, simple interest for 1 year = $280

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $280 × 10 = $2800

Thus, Simple Interest (SI) = $2800

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5600 + $2800

= $8400

Thus, Amount to be paid = $8400 Answer

Similar Questions

(1) Calculate the amount due if James borrowed a sum of $3000 at 10% simple interest for 3 years.

(2) Jessica took a loan of $5500 at the rate of 6% simple interest per annum. If he paid an amount of $7480 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due after 9 years if Susan borrowed a sum of $5650 at a rate of 2% simple interest.

(4) Jennifer took a loan of $4500 at the rate of 8% simple interest per annum. If he paid an amount of $7740 to clear the loan, then find the time period of the loan.

(5) Donald took a loan of $7000 at the rate of 8% simple interest per annum. If he paid an amount of $12040 to clear the loan, then find the time period of the loan.

(6) What amount does Jennifer have to pay after 6 years if he takes a loan of $3250 at 10% simple interest?

(7) Calculate the amount due after 10 years if Linda borrowed a sum of $5350 at a rate of 6% simple interest.

(8) Calculate the amount due if Christopher borrowed a sum of $4000 at 3% simple interest for 3 years.

(9) How much loan did Nancy borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $6765 to clear it?

(10) Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 5% simple interest.