Simple Interest
Math MCQs

Question :    Find the amount to be paid if John borrowed a sum of $5200 at 5% simple interest for 7 years.

Correct Answer  $7020

Solution & Explanation

Solution

Given,

Principal (P) = $5200

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) = $5200 × 5% × 7

= $5200 ×⁵/₁₀₀ × 7

= ^{5200 × 5 × 7}/₁₀₀

= ^{26000 × 7}/₁₀₀

= ¹⁸²⁰⁰⁰/₁₀₀

= $1820

Thus, Simple Interest = $1820

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 = $5200 + $1820

= $7020

Thus, Amount to be paid = $7020 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 = $5200

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

And, Time (t) = 7 years

Thus, Amount (A)

= $5200 + ($5200 × 5% × 7)

= $5200 + ($5200 ×⁵/₁₀₀ × 7)

= $5200 + (^{5200 × 5 × 7}/₁₀₀)

= $5200 + (^{26000 × 7}/₁₀₀)

= $5200 + (¹⁸²⁰⁰⁰/₁₀₀)

= $5200 + $1820 = $7020

Thus, Amount (A) to be paid = $7020 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 $5200, the simple interest in 1 year

= ⁵/₁₀₀ × 5200

= ^{5 × 5200}/₁₀₀

= ²⁶⁰⁰⁰/₁₀₀ = $260

Thus, simple interest for 1 year = $260

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $260 × 7 = $1820

Thus, Simple Interest (SI) = $1820

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5200 + $1820

= $7020

Thus, Amount to be paid = $7020 Answer

Similar Questions

(1) Calculate the amount due if Charles borrowed a sum of $3900 at 9% simple interest for 4 years.

(2) Jessica took a loan of $5500 at the rate of 6% simple interest per annum. If he paid an amount of $8800 to clear the loan, then find the time period of the loan.

(3) Sarah took a loan of $5700 at the rate of 9% simple interest per annum. If he paid an amount of $8778 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due if Linda borrowed a sum of $3350 at 3% simple interest for 3 years.

(5) Margaret took a loan of $6700 at the rate of 10% simple interest per annum. If he paid an amount of $13400 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Karen borrowed a sum of $3950 at 9% simple interest for 3 years.

(7) What amount does Barbara have to pay after 5 years if he takes a loan of $3550 at 10% simple interest?

(8) Find the amount to be paid if Jennifer borrowed a sum of $5250 at 9% simple interest for 7 years.

(9) Find the amount to be paid if John borrowed a sum of $5200 at 3% simple interest for 8 years.

(10) Find the amount to be paid if Linda borrowed a sum of $5350 at 2% simple interest for 7 years.