Simple Interest
Math MCQs

Question :    What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 7% simple interest?

Correct Answer  $5041

Solution & Explanation

Solution

Given,

Principal (P) = $3550

Rate of Simple Interest (SI) = 7%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 7% simple interest means, Rate of Simple Interest (SI) is 7% 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) = $3550 × 7% × 6

= $3550 ×⁷/₁₀₀ × 6

= ^{3550 × 7 × 6}/₁₀₀

= ^{24850 × 6}/₁₀₀

= ¹⁴⁹¹⁰⁰/₁₀₀

= $1491

Thus, Simple Interest = $1491

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 = $3550 + $1491

= $5041

Thus, Amount to be paid = $5041 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 = $3550

Rate of Simple Interest (SI) or (R) = 7%

And, Time (t) = 6 years

Thus, Amount (A)

= $3550 + ($3550 × 7% × 6)

= $3550 + ($3550 ×⁷/₁₀₀ × 6)

= $3550 + (^{3550 × 7 × 6}/₁₀₀)

= $3550 + (^{24850 × 6}/₁₀₀)

= $3550 + (¹⁴⁹¹⁰⁰/₁₀₀)

= $3550 + $1491 = $5041

Thus, Amount (A) to be paid = $5041 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 7%

This, means, $7 per $100 per year

∵ For $100, the simple interest for 1 year = $7

∴ For $1, the simple interest for 1 year = ⁷/₁₀₀

∴ For $3550, the simple interest in 1 year

= ⁷/₁₀₀ × 3550

= ^{7 × 3550}/₁₀₀

= ²⁴⁸⁵⁰/₁₀₀ = $248.5

Thus, simple interest for 1 year = $248.5

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $248.5 × 6 = $1491

Thus, Simple Interest (SI) = $1491

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3550 + $1491

= $5041

Thus, Amount to be paid = $5041 Answer

Similar Questions

(1) Calculate the amount due after 9 years if Jessica borrowed a sum of $5750 at a rate of 4% simple interest.

(2) Calculate the amount due after 9 years if Charles borrowed a sum of $5900 at a rate of 4% simple interest.

(3) Michael took a loan of $4600 at the rate of 7% simple interest per annum. If he paid an amount of $7176 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due if Richard borrowed a sum of $3600 at 2% simple interest for 4 years.

(5) James took a loan of $4000 at the rate of 6% simple interest per annum. If he paid an amount of $5440 to clear the loan, then find the time period of the loan.

(6) Linda took a loan of $4700 at the rate of 9% simple interest per annum. If he paid an amount of $7238 to clear the loan, then find the time period of the loan.

(7) What amount will be due after 2 years if William borrowed a sum of $3250 at a 5% simple interest?

(8) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 9% simple interest.

(9) Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 2% simple interest.

(10) Jennifer had to pay $3445 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.