Simple Interest
Math MCQs

Question :  ( 1 of 10 )  What amount does Michael have to pay after 6 years if he takes a loan of $3300 at 8% simple interest?

Correct Answer  $4884

Solution & Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 8%

Time (t) = 6 years

Thus, Amount (A) = ?

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

Thus, here 8% simple interest means, Rate of Simple Interest (SI) is 8% 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) = $3300 × 8% × 6

= $3300 ×⁸/₁₀₀ × 6

= ^{3300 × 8 × 6}/₁₀₀

= ^{26400 × 6}/₁₀₀

= ¹⁵⁸⁴⁰⁰/₁₀₀

= $1584

Thus, Simple Interest = $1584

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 = $3300 + $1584

= $4884

Thus, Amount to be paid = $4884 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 = $3300

Rate of Simple Interest (SI) or (R) = 8%

And, Time (t) = 6 years

Thus, Amount (A)

= $3300 + ($3300 × 8% × 6)

= $3300 + ($3300 ×⁸/₁₀₀ × 6)

= $3300 + (^{3300 × 8 × 6}/₁₀₀)

= $3300 + (^{26400 × 6}/₁₀₀)

= $3300 + (¹⁵⁸⁴⁰⁰/₁₀₀)

= $3300 + $1584 = $4884

Thus, Amount (A) to be paid = $4884 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 8%

This, means, $8 per $100 per year

∵ For $100, the simple interest for 1 year = $8

∴ For $1, the simple interest for 1 year = ⁸/₁₀₀

∴ For $3300, the simple interest in 1 year

= ⁸/₁₀₀ × 3300

= ^{8 × 3300}/₁₀₀

= ²⁶⁴⁰⁰/₁₀₀ = $264

Thus, simple interest for 1 year = $264

Therefore, simple interest for 6 years

= Simple interest for 1 year × 6

= $264 × 6 = $1584

Thus, Simple Interest (SI) = $1584

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $1584

= $4884

Thus, Amount to be paid = $4884 Answer

Similar Questions

(1) Calculate the amount due if Robert borrowed a sum of $3100 at 9% simple interest for 4 years.

(2) Calculate the amount due if Barbara borrowed a sum of $3550 at 3% simple interest for 3 years.

(3) Sandra took a loan of $6900 at the rate of 9% simple interest per annum. If he paid an amount of $13110 to clear the loan, then find the time period of the loan.

(4) Calculate the amount due if Karen borrowed a sum of $3950 at 8% simple interest for 3 years.

(5) Betty took a loan of $6500 at the rate of 7% simple interest per annum. If he paid an amount of $9230 to clear the loan, then find the time period of the loan.

(6) How much loan did Ashley borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $8187.5 to clear it?

(7) Calculate the amount due after 10 years if Patricia borrowed a sum of $5150 at a rate of 9% simple interest.

(8) How much loan did Elizabeth borrow 5 years ago at a rate of simple interest 4% per annum, if he paid $6540 to clear it?

(9) Find the amount to be paid if David borrowed a sum of $5400 at 5% simple interest for 8 years.

(10) In how much time a principal of $3200 will amount to $3840 at a simple interest of 4% per annum?