Simple Interest
MCQs Math


Question:     Calculate the amount due if John borrowed a sum of $3200 at 6% simple interest for 4 years.


Correct Answer  $3968

Solution And Explanation

Solution

Given,

Principal (P) = $3200

Rate of Simple Interest (SI) = 6%

Time (t) = 4 years

Thus, Amount (A) = ?

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

Thus, here 6% simple interest means, Rate of Simple Interest (SI) is 6% 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) = $3200 × 6% × 4

= $3200 ×6/100 × 4

= 3200 × 6 × 4/100

= 19200 × 4/100

= 76800/100

= $768

Thus, Simple Interest = $768

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 = $3200 + $768

= $3968

Thus, Amount to be paid = $3968 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 = $3200

Rate of Simple Interest (SI) or (R) = 6%

And, Time (t) = 4 years

Thus, Amount (A)

= $3200 + ($3200 × 6% × 4)

= $3200 + ($3200 ×6/100 × 4)

= $3200 + (3200 × 6 × 4/100)

= $3200 + (19200 × 4/100)

= $3200 + (76800/100)

= $3200 + $768 = $3968

Thus, Amount (A) to be paid = $3968 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 6%

This, means, $6 per $100 per year

∵ For $100, the simple interest for 1 year = $6

∴ For $1, the simple interest for 1 year = 6/100

∴ For $3200, the simple interest in 1 year

= 6/100 × 3200

= 6 × 3200/100

= 19200/100 = $192

Thus, simple interest for 1 year = $192

Therefore, simple interest for 4 years

= Simple interest for 1 year × 4

= $192 × 4 = $768

Thus, Simple Interest (SI) = $768

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3200 + $768

= $3968

Thus, Amount to be paid = $3968 Answer


Similar Questions

(1) Daniel had to pay $4346 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.

(2) Find the amount to be paid if Michael borrowed a sum of $5300 at 6% simple interest for 7 years.

(3) Calculate the amount due after 10 years if William borrowed a sum of $5500 at a rate of 6% simple interest.

(4) If Steven paid $5520 to settle his loan which he had taken 4 years before at a simple interest of 5%, then find the loan taken.

(5) If Robert borrowed $3100 from a bank at a rate of 3% simple interest per annum then find the amount to be paid after 2 years.

(6) Find the amount to be paid if John borrowed a sum of $5200 at 6% simple interest for 7 years.

(7) Matthew took a loan of $6400 at the rate of 6% simple interest per annum. If he paid an amount of $9088 to clear the loan, then find the time period of the loan.

(8) Find the amount to be paid if Elizabeth borrowed a sum of $5450 at 2% simple interest for 7 years.

(9) Jessica took a loan of $5500 at the rate of 8% simple interest per annum. If he paid an amount of $8580 to clear the loan, then find the time period of the loan.

(10) Joshua had to pay $5194 in order to furnish the loan taken 3 years before. If the rate of simple interest was 2% then find the sum borrowed.


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