Simple Interest
Math MCQs

Question :    Calculate the amount due after 10 years if Jennifer borrowed a sum of $5250 at a rate of 3% simple interest.

Correct Answer  $6825

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 3%

Time (t) = 10 years

Thus, Amount (A) = ?

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

Thus, here 3% simple interest means, Rate of Simple Interest (SI) is 3% 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 × 3% × 10

= $5250 ׳/₁₀₀ × 10

= ^{5250 × 3 × 10}/₁₀₀

= ^{15750 × 10}/₁₀₀

= ¹⁵⁷⁵⁰⁰/₁₀₀

= $1575

Thus, Simple Interest = $1575

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 + $1575

= $6825

Thus, Amount to be paid = $6825 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) = 3%

And, Time (t) = 10 years

Thus, Amount (A)

= $5250 + ($5250 × 3% × 10)

= $5250 + ($5250 ׳/₁₀₀ × 10)

= $5250 + (^{5250 × 3 × 10}/₁₀₀)

= $5250 + (^{15750 × 10}/₁₀₀)

= $5250 + (¹⁵⁷⁵⁰⁰/₁₀₀)

= $5250 + $1575 = $6825

Thus, Amount (A) to be paid = $6825 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 3%

This, means, $3 per $100 per year

∵ For $100, the simple interest for 1 year = $3

∴ For $1, the simple interest for 1 year = ³/₁₀₀

∴ For $5250, the simple interest in 1 year

= ³/₁₀₀ × 5250

= ^{3 × 5250}/₁₀₀

= ¹⁵⁷⁵⁰/₁₀₀ = $157.5

Thus, simple interest for 1 year = $157.5

Therefore, simple interest for 10 years

= Simple interest for 1 year × 10

= $157.5 × 10 = $1575

Thus, Simple Interest (SI) = $1575

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $1575

= $6825

Thus, Amount to be paid = $6825 Answer

Similar Questions

(1) Christopher took a loan of $6000 at the rate of 10% simple interest per annum. If he paid an amount of $12000 to clear the loan, then find the time period of the loan.

(2) Find the amount to be paid if John borrowed a sum of $5200 at 10% simple interest for 8 years.

(3) Linda took a loan of $4700 at the rate of 6% simple interest per annum. If he paid an amount of $6956 to clear the loan, then find the time period of the loan.

(4) Christopher took a loan of $6000 at the rate of 10% simple interest per annum. If he paid an amount of $10200 to clear the loan, then find the time period of the loan.

(5) Lisa took a loan of $6100 at the rate of 9% simple interest per annum. If he paid an amount of $9394 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Michael borrowed a sum of $3300 at 6% simple interest for 4 years.

(7) Find the amount to be paid if James borrowed a sum of $5000 at 3% simple interest for 8 years.

(8) Christopher took a loan of $6000 at the rate of 6% simple interest per annum. If he paid an amount of $9240 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due after 9 years if Robert borrowed a sum of $5100 at a rate of 5% simple interest.

(10) Find the amount to be paid if David borrowed a sum of $5400 at 8% simple interest for 8 years.