Simple Interest
Math MCQs

Question :    Calculate the amount due if Susan borrowed a sum of $3650 at 6% simple interest for 3 years.

Correct Answer  $4307

Solution & Explanation

Solution

Given,

Principal (P) = $3650

Rate of Simple Interest (SI) = 6%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $3650 × 6% × 3

= $3650 ×⁶/₁₀₀ × 3

= ^{3650 × 6 × 3}/₁₀₀

= ^{21900 × 3}/₁₀₀

= ⁶⁵⁷⁰⁰/₁₀₀

= $657

Thus, Simple Interest = $657

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 = $3650 + $657

= $4307

Thus, Amount to be paid = $4307 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 = $3650

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 3 years

Thus, Amount (A)

= $3650 + ($3650 × 6% × 3)

= $3650 + ($3650 ×⁶/₁₀₀ × 3)

= $3650 + (^{3650 × 6 × 3}/₁₀₀)

= $3650 + (^{21900 × 3}/₁₀₀)

= $3650 + (⁶⁵⁷⁰⁰/₁₀₀)

= $3650 + $657 = $4307

Thus, Amount (A) to be paid = $4307 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = ⁶/₁₀₀

∴ For $3650, the simple interest in 1 year

= ⁶/₁₀₀ × 3650

= ^{6 × 3650}/₁₀₀

= ²¹⁹⁰⁰/₁₀₀ = $219

Thus, simple interest for 1 year = $219

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $219 × 3 = $657

Thus, Simple Interest (SI) = $657

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3650 + $657

= $4307

Thus, Amount to be paid = $4307 Answer

Similar Questions

(1) What amount will be due after 2 years if Michael borrowed a sum of $3150 at a 6% simple interest?

(2) Mark took a loan of $6800 at the rate of 8% simple interest per annum. If he paid an amount of $10608 to clear the loan, then find the time period of the loan.

(3) If Emily paid $5510 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(4) Calculate the amount due after 9 years if Thomas borrowed a sum of $5800 at a rate of 6% simple interest.

(5) What amount will be due after 2 years if Mark borrowed a sum of $3700 at a 10% simple interest?

(6) If Christopher paid $4480 to settle his loan which he had taken 4 years before at a simple interest of 3%, then find the loan taken.

(7) Find the amount to be paid if Michael borrowed a sum of $5300 at 5% simple interest for 7 years.

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

(9) What amount will be due after 2 years if Christopher borrowed a sum of $3500 at a 4% simple interest?

(10) Margaret took a loan of $6700 at the rate of 8% simple interest per annum. If he paid an amount of $11524 to clear the loan, then find the time period of the loan.