Simple Interest
Math MCQs

Question :  ( 1 of 10 )  Calculate the amount due if Richard borrowed a sum of $3600 at 7% simple interest for 4 years.

Correct Answer  $4608

Solution & Explanation

Solution

Given,

Principal (P) = $3600

Rate of Simple Interest (SI) = 7%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 7% simple interest means, Rate of Simple Interest (SI) is 7% 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) = $3600 × 7% × 4

= $3600 ×⁷/₁₀₀ × 4

= ^{3600 × 7 × 4}/₁₀₀

= ^{25200 × 4}/₁₀₀

= ¹⁰⁰⁸⁰⁰/₁₀₀

= $1008

Thus, Simple Interest = $1008

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 = $3600 + $1008

= $4608

Thus, Amount to be paid = $4608 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 = $3600

Rate of Simple Interest (SI) or (R) = 7%

And, Time (t) = 4 years

Thus, Amount (A)

= $3600 + ($3600 × 7% × 4)

= $3600 + ($3600 ×⁷/₁₀₀ × 4)

= $3600 + (^{3600 × 7 × 4}/₁₀₀)

= $3600 + (^{25200 × 4}/₁₀₀)

= $3600 + (¹⁰⁰⁸⁰⁰/₁₀₀)

= $3600 + $1008 = $4608

Thus, Amount (A) to be paid = $4608 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 7%

This, means, $7 per $100 per year

∵ For $100, the simple interest for 1 year = $7

∴ For $1, the simple interest for 1 year = ⁷/₁₀₀

∴ For $3600, the simple interest in 1 year

= ⁷/₁₀₀ × 3600

= ^{7 × 3600}/₁₀₀

= ²⁵²⁰⁰/₁₀₀ = $252

Thus, simple interest for 1 year = $252

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $252 × 4 = $1008

Thus, Simple Interest (SI) = $1008

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3600 + $1008

= $4608

Thus, Amount to be paid = $4608 Answer

Similar Questions

(1) What amount does Jennifer have to pay after 5 years if he takes a loan of $3250 at 8% simple interest?

(2) In how much time a principal of $3150 will amount to $3937.5 at a simple interest of 5% per annum?

(3) Calculate the amount due after 10 years if John borrowed a sum of $5200 at a rate of 10% simple interest.

(4) Calculate the amount due after 10 years if Thomas borrowed a sum of $5800 at a rate of 10% simple interest.

(5) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 3% simple interest for 8 years.

(6) Calculate the amount due after 10 years if James borrowed a sum of $5000 at a rate of 8% simple interest.

(7) In how much time a principal of $3000 will amount to $3240 at a simple interest of 4% per annum?

(8) Calculate the amount due after 9 years if Sarah borrowed a sum of $5850 at a rate of 10% simple interest.

(9) Find the amount to be paid if John borrowed a sum of $5200 at 4% simple interest for 7 years.

(10) What amount does Linda have to pay after 6 years if he takes a loan of $3350 at 8% simple interest?