Simple Interest
MCQs Math


Question:     Calculate the amount due if Susan borrowed a sum of $3650 at 2% simple interest for 3 years.


Correct Answer  $3869

Solution And Explanation

Solution

Given,

Principal (P) = $3650

Rate of Simple Interest (SI) = 2%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 2% simple interest means, Rate of Simple Interest (SI) is 2% 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 × 2% × 3

= $3650 ×2/100 × 3

= 3650 × 2 × 3/100

= 7300 × 3/100

= 21900/100

= $219

Thus, Simple Interest = $219

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 + $219

= $3869

Thus, Amount to be paid = $3869 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) = 2%

And, Time (t) = 3 years

Thus, Amount (A)

= $3650 + ($3650 × 2% × 3)

= $3650 + ($3650 ×2/100 × 3)

= $3650 + (3650 × 2 × 3/100)

= $3650 + (7300 × 3/100)

= $3650 + (21900/100)

= $3650 + $219 = $3869

Thus, Amount (A) to be paid = $3869 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 2%

This, means, $2 per $100 per year

∵ For $100, the simple interest for 1 year = $2

∴ For $1, the simple interest for 1 year = 2/100

∴ For $3650, the simple interest in 1 year

= 2/100 × 3650

= 2 × 3650/100

= 7300/100 = $73

Thus, simple interest for 1 year = $73

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $73 × 3 = $219

Thus, Simple Interest (SI) = $219

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3650 + $219

= $3869

Thus, Amount to be paid = $3869 Answer


Similar Questions

(1) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 7% simple interest for 7 years.

(2) Calculate the amount due if Patricia borrowed a sum of $3150 at 9% simple interest for 3 years.

(3) Calculate the amount due if Thomas borrowed a sum of $3800 at 10% simple interest for 4 years.

(4) Find the amount to be paid if David borrowed a sum of $5400 at 7% simple interest for 8 years.

(5) Calculate the amount due after 9 years if Jennifer borrowed a sum of $5250 at a rate of 5% simple interest.

(6) If Matthew paid $4872 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(7) Mary took a loan of $4100 at the rate of 9% simple interest per annum. If he paid an amount of $7790 to clear the loan, then find the time period of the loan.

(8) David took a loan of $4800 at the rate of 10% simple interest per annum. If he paid an amount of $9600 to clear the loan, then find the time period of the loan.

(9) Calculate the amount due after 9 years if Patricia borrowed a sum of $5150 at a rate of 8% simple interest.

(10) What amount does Patricia have to pay after 5 years if he takes a loan of $3150 at 7% simple interest?


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