Simple Interest
Math MCQs

Question :    Calculate the amount due if Thomas borrowed a sum of $3800 at 4% simple interest for 4 years.

Correct Answer  $4408

Solution & Explanation

Solution

Given,

Principal (P) = $3800

Rate of Simple Interest (SI) = 4%

Time (t) = 4 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) = $3800 × 4% × 4

= $3800 ×⁴/₁₀₀ × 4

= ^{3800 × 4 × 4}/₁₀₀

= ^{15200 × 4}/₁₀₀

= ⁶⁰⁸⁰⁰/₁₀₀

= $608

Thus, Simple Interest = $608

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 = $3800 + $608

= $4408

Thus, Amount to be paid = $4408 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 = $3800

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

And, Time (t) = 4 years

Thus, Amount (A)

= $3800 + ($3800 × 4% × 4)

= $3800 + ($3800 ×⁴/₁₀₀ × 4)

= $3800 + (^{3800 × 4 × 4}/₁₀₀)

= $3800 + (^{15200 × 4}/₁₀₀)

= $3800 + (⁶⁰⁸⁰⁰/₁₀₀)

= $3800 + $608 = $4408

Thus, Amount (A) to be paid = $4408 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 $3800, the simple interest in 1 year

= ⁴/₁₀₀ × 3800

= ^{4 × 3800}/₁₀₀

= ¹⁵²⁰⁰/₁₀₀ = $152

Thus, simple interest for 1 year = $152

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $152 × 4 = $608

Thus, Simple Interest (SI) = $608

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3800 + $608

= $4408

Thus, Amount to be paid = $4408 Answer

Similar Questions

(1) Calculate the amount due if Linda borrowed a sum of $3350 at 3% simple interest for 3 years.

(2) John took a loan of $4400 at the rate of 10% simple interest per annum. If he paid an amount of $7920 to clear the loan, then find the time period of the loan.

(3) Find the amount to be paid if Christopher borrowed a sum of $6000 at 6% simple interest for 8 years.

(4) If Paul paid $5640 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(5) Anthony took a loan of $6600 at the rate of 6% simple interest per annum. If he paid an amount of $10560 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Michael borrowed a sum of $3300 at 3% simple interest for 3 years.

(7) Find the amount to be paid if William borrowed a sum of $5500 at 10% simple interest for 8 years.

(8) If Emily paid $5320 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(9) Joseph took a loan of $5400 at the rate of 8% simple interest per annum. If he paid an amount of $8424 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due if Jennifer borrowed a sum of $3250 at 3% simple interest for 3 years.