Simple Interest
Math MCQs

Question :  ( 1 of 10 )  Calculate the amount due if Linda borrowed a sum of $3350 at 9% simple interest for 4 years.

Correct Answer  $4556

Solution & Explanation

Solution

Given,

Principal (P) = $3350

Rate of Simple Interest (SI) = 9%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 9% simple interest means, Rate of Simple Interest (SI) is 9% 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 × 9% × 4

= $3350 ×⁹/₁₀₀ × 4

= ^{3350 × 9 × 4}/₁₀₀

= ^{30150 × 4}/₁₀₀

= ¹²⁰⁶⁰⁰/₁₀₀

= $1206

Thus, Simple Interest = $1206

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 + $1206

= $4556

Thus, Amount to be paid = $4556 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) = 9%

And, Time (t) = 4 years

Thus, Amount (A)

= $3350 + ($3350 × 9% × 4)

= $3350 + ($3350 ×⁹/₁₀₀ × 4)

= $3350 + (^{3350 × 9 × 4}/₁₀₀)

= $3350 + (^{30150 × 4}/₁₀₀)

= $3350 + (¹²⁰⁶⁰⁰/₁₀₀)

= $3350 + $1206 = $4556

Thus, Amount (A) to be paid = $4556 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 9%

This, means, $9 per $100 per year

∵ For $100, the simple interest for 1 year = $9

∴ For $1, the simple interest for 1 year = ⁹/₁₀₀

∴ For $3350, the simple interest in 1 year

= ⁹/₁₀₀ × 3350

= ^{9 × 3350}/₁₀₀

= ³⁰¹⁵⁰/₁₀₀ = $301.5

Thus, simple interest for 1 year = $301.5

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $301.5 × 4 = $1206

Thus, Simple Interest (SI) = $1206

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3350 + $1206

= $4556

Thus, Amount to be paid = $4556 Answer

Similar Questions

(1) What amount does David have to pay after 6 years if he takes a loan of $3400 at 9% simple interest?

(2) How much loan did Rebecca borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $8797.5 to clear it?

(3) In how much time a principal of $3000 will amount to $3180 at a simple interest of 2% per annum?

(4) How much loan did Mary borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $6312.5 to clear it?

(5) Calculate the amount due if William borrowed a sum of $3500 at 8% simple interest for 3 years.

(6) Robert took a loan of $4200 at the rate of 7% simple interest per annum. If he paid an amount of $5964 to clear the loan, then find the time period of the loan.

(7) How much loan did John borrow 5 years ago at a rate of simple interest 5% per annum, if he paid $6500 to clear it?

(8) Find the amount to be paid if Richard borrowed a sum of $5600 at 3% simple interest for 7 years.

(9) What amount does Jessica have to pay after 6 years if he takes a loan of $3750 at 9% simple interest?

(10) How much loan did Mark borrow 5 years ago at a rate of simple interest 3% per annum, if he paid $7360 to clear it?