Simple Interest
Math MCQs

Question :    Calculate the amount due if Jennifer borrowed a sum of $3250 at 4% simple interest for 3 years.

Correct Answer  $3640

Solution & Explanation

Solution

Given,

Principal (P) = $3250

Rate of Simple Interest (SI) = 4%

Time (t) = 3 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) = $3250 × 4% × 3

= $3250 ×⁴/₁₀₀ × 3

= ^{3250 × 4 × 3}/₁₀₀

= ^{13000 × 3}/₁₀₀

= ³⁹⁰⁰⁰/₁₀₀

= $390

Thus, Simple Interest = $390

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 = $3250 + $390

= $3640

Thus, Amount to be paid = $3640 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 = $3250

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

And, Time (t) = 3 years

Thus, Amount (A)

= $3250 + ($3250 × 4% × 3)

= $3250 + ($3250 ×⁴/₁₀₀ × 3)

= $3250 + (^{3250 × 4 × 3}/₁₀₀)

= $3250 + (^{13000 × 3}/₁₀₀)

= $3250 + (³⁹⁰⁰⁰/₁₀₀)

= $3250 + $390 = $3640

Thus, Amount (A) to be paid = $3640 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 $3250, the simple interest in 1 year

= ⁴/₁₀₀ × 3250

= ^{4 × 3250}/₁₀₀

= ¹³⁰⁰⁰/₁₀₀ = $130

Thus, simple interest for 1 year = $130

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $130 × 3 = $390

Thus, Simple Interest (SI) = $390

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3250 + $390

= $3640

Thus, Amount to be paid = $3640 Answer

Similar Questions

(1) Find the amount to be paid if William borrowed a sum of $5500 at 5% simple interest for 8 years.

(2) Donald took a loan of $7000 at the rate of 9% simple interest per annum. If he paid an amount of $10780 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 6% simple interest for 3 years.

(4) Paul had to pay $4982 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(5) William had to pay $3710 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(6) Charles took a loan of $5800 at the rate of 6% simple interest per annum. If he paid an amount of $8584 to clear the loan, then find the time period of the loan.

(7) If Matthew paid $4536 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(8) Robert took a loan of $4200 at the rate of 6% simple interest per annum. If he paid an amount of $6468 to clear the loan, then find the time period of the loan.

(9) Find the amount to be paid if Susan borrowed a sum of $5650 at 7% simple interest for 8 years.

(10) What amount will be due after 2 years if Charles borrowed a sum of $3450 at a 5% simple interest?