Simple Interest
Math MCQs

Question :    Calculate the amount due if Patricia borrowed a sum of $3150 at 2% simple interest for 4 years.

Correct Answer  $3402

Solution & Explanation

Solution

Given,

Principal (P) = $3150

Rate of Simple Interest (SI) = 2%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 2% simple interest means, Rate of Simple Interest (SI) is 2% 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) = $3150 × 2% × 4

= $3150 ײ/₁₀₀ × 4

= ^{3150 × 2 × 4}/₁₀₀

= ^{6300 × 4}/₁₀₀

= ²⁵²⁰⁰/₁₀₀

= $252

Thus, Simple Interest = $252

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 = $3150 + $252

= $3402

Thus, Amount to be paid = $3402 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 = $3150

Rate of Simple Interest (SI) or (R) = 2%

And, Time (t) = 4 years

Thus, Amount (A)

= $3150 + ($3150 × 2% × 4)

= $3150 + ($3150 ײ/₁₀₀ × 4)

= $3150 + (^{3150 × 2 × 4}/₁₀₀)

= $3150 + (^{6300 × 4}/₁₀₀)

= $3150 + (²⁵²⁰⁰/₁₀₀)

= $3150 + $252 = $3402

Thus, Amount (A) to be paid = $3402 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 2%

This, means, $2 per $100 per year

∵ For $100, the simple interest for 1 year = $2

∴ For $1, the simple interest for 1 year = ²/₁₀₀

∴ For $3150, the simple interest in 1 year

= ²/₁₀₀ × 3150

= ^{2 × 3150}/₁₀₀

= ⁶³⁰⁰/₁₀₀ = $63

Thus, simple interest for 1 year = $63

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $63 × 4 = $252

Thus, Simple Interest (SI) = $252

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3150 + $252

= $3402

Thus, Amount to be paid = $3402 Answer

Similar Questions

(1) Mary took a loan of $4100 at the rate of 7% simple interest per annum. If he paid an amount of $6683 to clear the loan, then find the time period of the loan.

(2) If John paid $3712 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(3) If Kenneth paid $5600 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(4) In how much time a principal of $3000 will amount to $3180 at a simple interest of 3% per annum?

(5) Calculate the amount due if Patricia borrowed a sum of $3150 at 5% simple interest for 4 years.

(6) What amount will be due after 2 years if Robert borrowed a sum of $3050 at a 10% simple interest?

(7) Lisa took a loan of $6100 at the rate of 7% simple interest per annum. If he paid an amount of $9943 to clear the loan, then find the time period of the loan.

(8) Christopher took a loan of $6000 at the rate of 6% simple interest per annum. If he paid an amount of $8880 to clear the loan, then find the time period of the loan.

(9) Sandra took a loan of $6900 at the rate of 9% simple interest per annum. If he paid an amount of $12489 to clear the loan, then find the time period of the loan.

(10) Mary took a loan of $4100 at the rate of 10% simple interest per annum. If he paid an amount of $6560 to clear the loan, then find the time period of the loan.