Simple Interest
Math MCQs

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

Correct Answer  $6667.5

Solution & Explanation

Solution

Given,

Principal (P) = $5250

Rate of Simple Interest (SI) = 3%

Time (t) = 9 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% × 9

= $5250 ׳/₁₀₀ × 9

= ^{5250 × 3 × 9}/₁₀₀

= ^{15750 × 9}/₁₀₀

= ¹⁴¹⁷⁵⁰/₁₀₀

= $1417.5

Thus, Simple Interest = $1417.5

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 + $1417.5

= $6667.5

Thus, Amount to be paid = $6667.5 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) = 9 years

Thus, Amount (A)

= $5250 + ($5250 × 3% × 9)

= $5250 + ($5250 ׳/₁₀₀ × 9)

= $5250 + (^{5250 × 3 × 9}/₁₀₀)

= $5250 + (^{15750 × 9}/₁₀₀)

= $5250 + (¹⁴¹⁷⁵⁰/₁₀₀)

= $5250 + $1417.5 = $6667.5

Thus, Amount (A) to be paid = $6667.5 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 9 years

= Simple interest for 1 year × 9

= $157.5 × 9 = $1417.5

Thus, Simple Interest (SI) = $1417.5

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5250 + $1417.5

= $6667.5

Thus, Amount to be paid = $6667.5 Answer

Similar Questions

(1) Calculate the amount due after 9 years if Mary borrowed a sum of $5050 at a rate of 3% simple interest.

(2) Karen took a loan of $5900 at the rate of 9% simple interest per annum. If he paid an amount of $9086 to clear the loan, then find the time period of the loan.

(3) Calculate the amount due if Charles borrowed a sum of $3900 at 9% simple interest for 3 years.

(4) John took a loan of $4400 at the rate of 9% simple interest per annum. If he paid an amount of $8360 to clear the loan, then find the time period of the loan.

(5) How much loan did Steven borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7920 to clear it?

(6) Joseph had to pay $3922 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(7) Michael took a loan of $4600 at the rate of 10% simple interest per annum. If he paid an amount of $7360 to clear the loan, then find the time period of the loan.

(8) David took a loan of $4800 at the rate of 6% simple interest per annum. If he paid an amount of $6816 to clear the loan, then find the time period of the loan.

(9) Find the amount to be paid if Richard borrowed a sum of $5600 at 7% simple interest for 7 years.

(10) Find the amount to be paid if John borrowed a sum of $5200 at 10% simple interest for 7 years.