Simple Interest
Math MCQs

Question :    What amount does Barbara have to pay after 6 years if he takes a loan of $3550 at 4% simple interest?

Correct Answer  $4402

Solution & Explanation

Solution

Given,

Principal (P) = $3550

Rate of Simple Interest (SI) = 4%

Time (t) = 6 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) = $3550 × 4% × 6

= $3550 ×⁴/₁₀₀ × 6

= ^{3550 × 4 × 6}/₁₀₀

= ^{14200 × 6}/₁₀₀

= ⁸⁵²⁰⁰/₁₀₀

= $852

Thus, Simple Interest = $852

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 = $3550 + $852

= $4402

Thus, Amount to be paid = $4402 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 = $3550

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

And, Time (t) = 6 years

Thus, Amount (A)

= $3550 + ($3550 × 4% × 6)

= $3550 + ($3550 ×⁴/₁₀₀ × 6)

= $3550 + (^{3550 × 4 × 6}/₁₀₀)

= $3550 + (^{14200 × 6}/₁₀₀)

= $3550 + (⁸⁵²⁰⁰/₁₀₀)

= $3550 + $852 = $4402

Thus, Amount (A) to be paid = $4402 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 $3550, the simple interest in 1 year

= ⁴/₁₀₀ × 3550

= ^{4 × 3550}/₁₀₀

= ¹⁴²⁰⁰/₁₀₀ = $142

Thus, simple interest for 1 year = $142

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $142 × 6 = $852

Thus, Simple Interest (SI) = $852

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3550 + $852

= $4402

Thus, Amount to be paid = $4402 Answer

Similar Questions

(1) If David borrowed $3400 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 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) Margaret had to pay $5002.5 in order to furnish the loan taken 3 years before. If the rate of simple interest was 5% then find the sum borrowed.

(4) Calculate the amount due after 9 years if Michael borrowed a sum of $5300 at a rate of 9% simple interest.

(5) Mark took a loan of $6800 at the rate of 9% simple interest per annum. If he paid an amount of $12920 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Patricia borrowed a sum of $3150 at 4% simple interest for 3 years.

(7) What amount does Michael have to pay after 6 years if he takes a loan of $3300 at 10% simple interest?

(8) If Richard paid $3888 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(9) What amount will be due after 2 years if John borrowed a sum of $3100 at a 4% simple interest?

(10) Find the amount to be paid if Barbara borrowed a sum of $5550 at 6% simple interest for 8 years.