Simple Interest
Math MCQs

Question :    Calculate the amount due if Linda borrowed a sum of $3350 at 4% simple interest for 3 years.

Correct Answer  $3752

Solution & Explanation

Solution

Given,

Principal (P) = $3350

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) = $3350 × 4% × 3

= $3350 ×⁴/₁₀₀ × 3

= ^{3350 × 4 × 3}/₁₀₀

= ^{13400 × 3}/₁₀₀

= ⁴⁰²⁰⁰/₁₀₀

= $402

Thus, Simple Interest = $402

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 = $3350 + $402

= $3752

Thus, Amount to be paid = $3752 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 = $3350

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

And, Time (t) = 3 years

Thus, Amount (A)

= $3350 + ($3350 × 4% × 3)

= $3350 + ($3350 ×⁴/₁₀₀ × 3)

= $3350 + (^{3350 × 4 × 3}/₁₀₀)

= $3350 + (^{13400 × 3}/₁₀₀)

= $3350 + (⁴⁰²⁰⁰/₁₀₀)

= $3350 + $402 = $3752

Thus, Amount (A) to be paid = $3752 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 $3350, the simple interest in 1 year

= ⁴/₁₀₀ × 3350

= ^{4 × 3350}/₁₀₀

= ¹³⁴⁰⁰/₁₀₀ = $134

Thus, simple interest for 1 year = $134

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $134 × 3 = $402

Thus, Simple Interest (SI) = $402

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3350 + $402

= $3752

Thus, Amount to be paid = $3752 Answer

Similar Questions

(1) How much loan did Matthew borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $7440 to clear it?

(2) Find the amount to be paid if Mary borrowed a sum of $5050 at 6% simple interest for 7 years.

(3) Christopher took a loan of $6000 at the rate of 8% simple interest per annum. If he paid an amount of $10800 to clear the loan, then find the time period of the loan.

(4) In how much time a principal of $3150 will amount to $3528 at a simple interest of 3% per annum?

(5) Find the amount to be paid if Susan borrowed a sum of $5650 at 4% simple interest for 8 years.

(6) Calculate the amount due after 9 years if Barbara borrowed a sum of $5550 at a rate of 5% simple interest.

(7) What amount will be due after 2 years if Joshua borrowed a sum of $3950 at a 5% simple interest?

(8) John took a loan of $4400 at the rate of 8% simple interest per annum. If he paid an amount of $7568 to clear the loan, then find the time period of the loan.

(9) Michael took a loan of $4600 at the rate of 6% simple interest per annum. If he paid an amount of $7084 to clear the loan, then find the time period of the loan.

(10) If William paid $3780 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.