Simple Interest
Math MCQs

Question :    Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 6% simple interest for 7 years.

Correct Answer  $7739

Solution & Explanation

Solution

Given,

Principal (P) = $5450

Rate of Simple Interest (SI) = 6%

Time (t) = 7 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $5450 × 6% × 7

= $5450 ×⁶/₁₀₀ × 7

= ^{5450 × 6 × 7}/₁₀₀

= ^{32700 × 7}/₁₀₀

= ²²⁸⁹⁰⁰/₁₀₀

= $2289

Thus, Simple Interest = $2289

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 = $5450 + $2289

= $7739

Thus, Amount to be paid = $7739 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 = $5450

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 7 years

Thus, Amount (A)

= $5450 + ($5450 × 6% × 7)

= $5450 + ($5450 ×⁶/₁₀₀ × 7)

= $5450 + (^{5450 × 6 × 7}/₁₀₀)

= $5450 + (^{32700 × 7}/₁₀₀)

= $5450 + (²²⁸⁹⁰⁰/₁₀₀)

= $5450 + $2289 = $7739

Thus, Amount (A) to be paid = $7739 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $5450, the simple interest in 1 year

= ⁶/₁₀₀ × 5450

= ^{6 × 5450}/₁₀₀

= ³²⁷⁰⁰/₁₀₀ = $327

Thus, simple interest for 1 year = $327

Therefore, simple interest for 7 years

= Simple interest for 1 year × 7

= $327 × 7 = $2289

Thus, Simple Interest (SI) = $2289

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5450 + $2289

= $7739

Thus, Amount to be paid = $7739 Answer

Similar Questions

(1) Calculate the amount due if Richard borrowed a sum of $3600 at 9% simple interest for 4 years.

(2) What amount does Robert have to pay after 5 years if he takes a loan of $3100 at 5% simple interest?

(3) Find the amount to be paid if William borrowed a sum of $5500 at 2% simple interest for 7 years.

(4) Matthew took a loan of $6400 at the rate of 9% simple interest per annum. If he paid an amount of $12160 to clear the loan, then find the time period of the loan.

(5) Calculate the amount due after 9 years if Richard borrowed a sum of $5600 at a rate of 8% simple interest.

(6) Karen took a loan of $5900 at the rate of 9% simple interest per annum. If he paid an amount of $11210 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due if Karen borrowed a sum of $3950 at 10% simple interest for 3 years.

(8) Calculate the amount due after 10 years if Karen borrowed a sum of $5950 at a rate of 4% simple interest.

(9) Jennifer took a loan of $4500 at the rate of 7% simple interest per annum. If he paid an amount of $6705 to clear the loan, then find the time period of the loan.

(10) What amount does Thomas have to pay after 6 years if he takes a loan of $3800 at 2% simple interest?