Question

Ali bought 3 notebooks and 2 books with $ 42, knowing that the price of a notebook is half the price of a book, what is the price of a notebook and a book?

Answer 1

Answer: Rs. 6 and Rs. 12

Solution:

We are given that 3 notebooks and 2 books together costs Rs. 42. Price of notebook is half the price of book. We need to find the cost of each notebook and book.

Let us assume the cost of notebook as 'x' and cost of book as 'y'. According to the question,

⇒ 3x + 2y = 42 ---(Eq.1)

We also know that,

⇒ x = y/2

⇒ 2x = y ---(Eq.2)

Let us substitute the value of y = 2x in Eq.(1):

⇒ 3x + 2y = 42

⇒ 3x + 2(2x) = 42

⇒ 3x + 4x = 42

⇒ 7x = 42

⇒ x = 42/7

⇒ x = 6

Let us substitute the value of x in Eq.(2):

⇒ 2x = y

⇒ 2 × 6 = y

⇒ 12 = y

Hence, the cost of notebook is Rs. 6 and Cost of book is Rs.12.

Verification:

Let us verify whether the cost of notebook and book is correct or wrong. Let us consider Eq.(1):

⇒ 3x + 2y = 42

[We know that x = 6 and y = 12]

⇒ 3(6) + 2(12) = 42

⇒ 18 + 24 = 42

⇒ 42 = 42

Hence, our evaluation is correct!