Let the cost of pencils be x and cost of pens be y.

The linear equations formed are:

5x + 7y = 195 … (1)

7x + 5y = 153 … (2)

We know that the general form for a pair of linear equations in 2 variables x and y is a₁x + b₁y + c₁ = 0

and a₂x + b₂y + c₂ = 0.

Comparing with above equations,

we have a₁ = 5, b₁ = 7, c₁ = - 195; a₂ = 7, b₂ = 5, c₂ = - 153

We can solve by cross multiplication method using the formula

Substituting values in the formula, we get

⇒

⇒

⇒ and

⇒ x = 4 and y = 25

The cost of each pencil is Rs.4 and cost of each pen is Rs.25.