Simple Interest
Math MCQs

Question :    Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 4% simple interest.

Correct Answer  $7140

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 4%

Time (t) = 9 years

Thus, Amount (A) = ?

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

Thus, here 4% simple interest means, Rate of Simple Interest (SI) is 4% 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) = $5250 × 4% × 9

= $5250 ×⁴/₁₀₀ × 9

= ^{5250 × 4 × 9}/₁₀₀

= ^{21000 × 9}/₁₀₀

= ¹⁸⁹⁰⁰⁰/₁₀₀

= $1890

Thus, Simple Interest = $1890

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 = $5250 + $1890

= $7140

Thus, Amount to be paid = $7140 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 = $5250

Rate of Simple Interest (SI) or (R) = 4%

And, Time (t) = 9 years

Thus, Amount (A)

= $5250 + ($5250 × 4% × 9)

= $5250 + ($5250 ×⁴/₁₀₀ × 9)

= $5250 + (^{5250 × 4 × 9}/₁₀₀)

= $5250 + (^{21000 × 9}/₁₀₀)

= $5250 + (¹⁸⁹⁰⁰⁰/₁₀₀)

= $5250 + $1890 = $7140

Thus, Amount (A) to be paid = $7140 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 4%

This, means, $4 per $100 per year

∵ For $100, the simple interest for 1 year = $4

∴ For $1, the simple interest for 1 year = ⁴/₁₀₀

∴ For $5250, the simple interest in 1 year

= ⁴/₁₀₀ × 5250

= ^{4 × 5250}/₁₀₀

= ²¹⁰⁰⁰/₁₀₀ = $210

Thus, simple interest for 1 year = $210

Therefore, simple interest for 9 years

= Simple interest for 1 year × 9

= $210 × 9 = $1890

Thus, Simple Interest (SI) = $1890

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $1890

= $7140

Thus, Amount to be paid = $7140 Answer

Similar Questions

(1) Michael took a loan of $4600 at the rate of 10% simple interest per annum. If he paid an amount of $9200 to clear the loan, then find the time period of the loan.

(2) Find the amount to be paid if Barbara borrowed a sum of $5550 at 9% simple interest for 7 years.

(3) Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 8% simple interest.

(4) Find the amount to be paid if Mary borrowed a sum of $5050 at 7% simple interest for 8 years.

(5) Mark took a loan of $6800 at the rate of 6% simple interest per annum. If he paid an amount of $10880 to clear the loan, then find the time period of the loan.

(6) Donald took a loan of $7000 at the rate of 10% simple interest per annum. If he paid an amount of $11900 to clear the loan, then find the time period of the loan.

(7) Calculate the amount due after 9 years if Barbara borrowed a sum of $5550 at a rate of 6% simple interest.

(8) Anthony had to pay $4687 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(9) William took a loan of $5000 at the rate of 8% simple interest per annum. If he paid an amount of $7400 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 2% simple interest.