The cost of a notebook is twice the cost of a pen. Write a linear equation in two variables to represent this statement.
(Take the cost of a notebook to be Rs. x and that of a pen to be Rs. y)

Let the cost of a notebook = Rs. x and the cost of a pen = Rs. y

According to question,

Cost of a Notebook = ( Cost of a 2 Pen)
x = 2y
Therefore the equation, x - 2y = 0 represents this statement.