Simple Interest
Math MCQs

Question :    Find the amount to be paid if Patricia borrowed a sum of $5150 at 3% simple interest for 8 years.

Correct Answer  $6386

Solution & Explanation

Solution

Given,

Principal (P) = $5150

Rate of Simple Interest (SI) = 3%

Time (t) = 8 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) = $5150 × 3% × 8

= $5150 ׳/₁₀₀ × 8

= ^{5150 × 3 × 8}/₁₀₀

= ^{15450 × 8}/₁₀₀

= ¹²³⁶⁰⁰/₁₀₀

= $1236

Thus, Simple Interest = $1236

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 = $5150 + $1236

= $6386

Thus, Amount to be paid = $6386 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 = $5150

Rate of Simple Interest (SI) or (R) = 3%

And, Time (t) = 8 years

Thus, Amount (A)

= $5150 + ($5150 × 3% × 8)

= $5150 + ($5150 ׳/₁₀₀ × 8)

= $5150 + (^{5150 × 3 × 8}/₁₀₀)

= $5150 + (^{15450 × 8}/₁₀₀)

= $5150 + (¹²³⁶⁰⁰/₁₀₀)

= $5150 + $1236 = $6386

Thus, Amount (A) to be paid = $6386 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 $5150, the simple interest in 1 year

= ³/₁₀₀ × 5150

= ^{3 × 5150}/₁₀₀

= ¹⁵⁴⁵⁰/₁₀₀ = $154.5

Thus, simple interest for 1 year = $154.5

Therefore, simple interest for 8 years

= Simple interest for 1 year × 8

= $154.5 × 8 = $1236

Thus, Simple Interest (SI) = $1236

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $5150 + $1236

= $6386

Thus, Amount to be paid = $6386 Answer

Similar Questions

(1) How much loan did Brian borrow 5 years ago at a rate of simple interest 2% per annum, if he paid $7920 to clear it?

(2) Calculate the amount due after 10 years if Barbara borrowed a sum of $5550 at a rate of 9% simple interest.

(3) If Michelle paid $5346 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(4) Calculate the amount due after 9 years if John borrowed a sum of $5200 at a rate of 7% simple interest.

(5) Donald took a loan of $7000 at the rate of 9% simple interest per annum. If he paid an amount of $12040 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due after 9 years if Joseph borrowed a sum of $5700 at a rate of 9% simple interest.

(7) Calculate the amount due if Christopher borrowed a sum of $4000 at 10% simple interest for 4 years.

(8) Daniel had to pay $4469 in order to furnish the loan taken 3 years before. If the rate of simple interest was 3% then find the sum borrowed.

(9) Robert took a loan of $4200 at the rate of 9% simple interest per annum. If he paid an amount of $7980 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due after 9 years if Christopher borrowed a sum of $6000 at a rate of 3% simple interest.