Simple Interest
MCQs Math


Question:     Calculate the amount due if Michael borrowed a sum of $3300 at 10% simple interest for 3 years.


Correct Answer  $4290

Solution And Explanation

Solution

Given,

Principal (P) = $3300

Rate of Simple Interest (SI) = 10%

Time (t) = 3 years

Thus, Amount (A) = ?

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

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% 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 × 10% × 3

= $3300 ×10/100 × 3

= 3300 × 10 × 3/100

= 33000 × 3/100

= 99000/100

= $990

Thus, Simple Interest = $990

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 + $990

= $4290

Thus, Amount to be paid = $4290 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) = 10%

And, Time (t) = 3 years

Thus, Amount (A)

= $3300 + ($3300 × 10% × 3)

= $3300 + ($3300 ×10/100 × 3)

= $3300 + (3300 × 10 × 3/100)

= $3300 + (33000 × 3/100)

= $3300 + (99000/100)

= $3300 + $990 = $4290

Thus, Amount (A) to be paid = $4290 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = 10/100

∴ For $3300, the simple interest in 1 year

= 10/100 × 3300

= 10 × 3300/100

= 33000/100 = $330

Thus, simple interest for 1 year = $330

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $330 × 3 = $990

Thus, Simple Interest (SI) = $990

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3300 + $990

= $4290

Thus, Amount to be paid = $4290 Answer


Similar Questions

(1) What amount does John have to pay after 5 years if he takes a loan of $3200 at 8% simple interest?

(2) Thomas took a loan of $5600 at the rate of 10% simple interest per annum. If he paid an amount of $11200 to clear the loan, then find the time period of the loan.

(3) Find the amount to be paid if Michael borrowed a sum of $5300 at 8% simple interest for 8 years.

(4) Find the amount to be paid if Jessica borrowed a sum of $5750 at 9% simple interest for 8 years.

(5) Nancy took a loan of $6300 at the rate of 6% simple interest per annum. If he paid an amount of $8568 to clear the loan, then find the time period of the loan.

(6) Calculate the amount due if Joseph borrowed a sum of $3700 at 4% simple interest for 3 years.

(7) Calculate the amount due after 10 years if Elizabeth borrowed a sum of $5450 at a rate of 10% simple interest.

(8) What amount will be due after 2 years if Christopher borrowed a sum of $3500 at a 8% simple interest?

(9) If William paid $4060 to settle his loan which he had taken 4 years before at a simple interest of 4%, then find the loan taken.

(10) What amount does Karen have to pay after 5 years if he takes a loan of $3950 at 3% simple interest?


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