Simple Interest
Math MCQs

Question :    Find the amount to be paid if Thomas borrowed a sum of $5800 at 5% simple interest for 7 years.

Correct Answer  $7830

Solution & Explanation

Solution

Given,

Principal (P) = $5800

Rate of Simple Interest (SI) = 5%

Time (t) = 7 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) = $5800 × 5% × 7

= $5800 ×⁵/₁₀₀ × 7

= ^{5800 × 5 × 7}/₁₀₀

= ^{29000 × 7}/₁₀₀

= ²⁰³⁰⁰⁰/₁₀₀

= $2030

Thus, Simple Interest = $2030

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 = $5800 + $2030

= $7830

Thus, Amount to be paid = $7830 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 = $5800

Rate of Simple Interest (SI) or (R) = 5%

And, Time (t) = 7 years

Thus, Amount (A)

= $5800 + ($5800 × 5% × 7)

= $5800 + ($5800 ×⁵/₁₀₀ × 7)

= $5800 + (^{5800 × 5 × 7}/₁₀₀)

= $5800 + (^{29000 × 7}/₁₀₀)

= $5800 + (²⁰³⁰⁰⁰/₁₀₀)

= $5800 + $2030 = $7830

Thus, Amount (A) to be paid = $7830 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 $5800, the simple interest in 1 year

= ⁵/₁₀₀ × 5800

= ^{5 × 5800}/₁₀₀

= ²⁹⁰⁰⁰/₁₀₀ = $290

Thus, simple interest for 1 year = $290

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $290 × 7 = $2030

Thus, Simple Interest (SI) = $2030

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5800 + $2030

= $7830

Thus, Amount to be paid = $7830 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 after 10 years if Patricia borrowed a sum of $5150 at a rate of 9% simple interest.

(3) Robert took a loan of $4200 at the rate of 7% simple interest per annum. If he paid an amount of $6258 to clear the loan, then find the time period of the loan.

(4) David took a loan of $4800 at the rate of 7% simple interest per annum. If he paid an amount of $7824 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due if Thomas borrowed a sum of $3800 at 2% simple interest for 4 years.

(6) Mary took a loan of $4100 at the rate of 10% simple interest per annum. If he paid an amount of $7790 to clear the loan, then find the time period of the loan.

(7) Donald took a loan of $7000 at the rate of 6% simple interest per annum. If he paid an amount of $10780 to clear the loan, then find the time period of the loan.

(8) Find the amount to be paid if Robert borrowed a sum of $5100 at 9% simple interest for 7 years.

(9) What amount does John have to pay after 5 years if he takes a loan of $3200 at 8% simple interest?

(10) Margaret took a loan of $6700 at the rate of 10% simple interest per annum. If he paid an amount of $10720 to clear the loan, then find the time period of the loan.