(Q.38). 5 pencils and 7 pens together cost Rs. 50 whereas 7 pencils and 5 pens together cost Rs. 46. Find the cost of one pencil and that of one pen.

Let the cost of each pencil be Rs. x

and the cost of each pen be Rs. y.

By problem x + y = 50

x + y = 46

5x + 7y = 50
x y (x,y)
3 (3,)
10 (10,)
7x + 5y = 46
x y (x,y)
8 - (8,-)
3 (3,)

The lines are intersecting at the point (, ).

x = and y = is the solution of given equations.

∴ Cost of one pencil = Rs. and pen = Rs.