Simple Interest
Math MCQs

Question :    What amount does Patricia have to pay after 6 years if he takes a loan of $3150 at 4% simple interest?

Correct Answer  $3906

Solution & Explanation

Solution

Given,

Principal (P) = $3150

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) = $3150 × 4% × 6

= $3150 ×⁴/₁₀₀ × 6

= ^{3150 × 4 × 6}/₁₀₀

= ^{12600 × 6}/₁₀₀

= ⁷⁵⁶⁰⁰/₁₀₀

= $756

Thus, Simple Interest = $756

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 = $3150 + $756

= $3906

Thus, Amount to be paid = $3906 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 = $3150

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

And, Time (t) = 6 years

Thus, Amount (A)

= $3150 + ($3150 × 4% × 6)

= $3150 + ($3150 ×⁴/₁₀₀ × 6)

= $3150 + (^{3150 × 4 × 6}/₁₀₀)

= $3150 + (^{12600 × 6}/₁₀₀)

= $3150 + (⁷⁵⁶⁰⁰/₁₀₀)

= $3150 + $756 = $3906

Thus, Amount (A) to be paid = $3906 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 $3150, the simple interest in 1 year

= ⁴/₁₀₀ × 3150

= ^{4 × 3150}/₁₀₀

= ¹²⁶⁰⁰/₁₀₀ = $126

Thus, simple interest for 1 year = $126

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $126 × 6 = $756

Thus, Simple Interest (SI) = $756

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3150 + $756

= $3906

Thus, Amount to be paid = $3906 Answer

Similar Questions

(1) Find the amount to be paid if James borrowed a sum of $5000 at 4% simple interest for 8 years.

(2) Calculate the amount due if William borrowed a sum of $3500 at 7% simple interest for 3 years.

(3) Calculate the amount due after 9 years if Joseph borrowed a sum of $5700 at a rate of 8% simple interest.

(4) Lisa took a loan of $6100 at the rate of 7% simple interest per annum. If he paid an amount of $10370 to clear the loan, then find the time period of the loan.

(5) Daniel took a loan of $6200 at the rate of 8% simple interest per annum. If he paid an amount of $9176 to clear the loan, then find the time period of the loan.

(6) What amount does Joseph have to pay after 6 years if he takes a loan of $3700 at 5% simple interest?

(7) Betty took a loan of $6500 at the rate of 9% simple interest per annum. If he paid an amount of $11765 to clear the loan, then find the time period of the loan.

(8) Matthew took a loan of $6400 at the rate of 9% simple interest per annum. If he paid an amount of $9856 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due if John borrowed a sum of $3200 at 8% simple interest for 3 years.

(10) In how much time a principal of $3000 will amount to $3750 at a simple interest of 5% per annum?