Question

The cost of two pencilsand 3 pens together is rupees 14 the cost of 3 pencilsand 5 pens if the same is 22 write equation to the above informatin

Answer 1

let the one pencil cost be rs x

and the one pen cost be rs y

case I :

            2x + 3y = 14........eq1

case II :

           3x + 5y  = 22..........eq2

subtract eq 1 from 2

   3x+5y-(2x+3y) = 22-14

3x+ 5y - 2x -3y = 8

x+2y = 8

x= 8 -2y

(put in eq 1)

2(8-2y) + 3y = 14

16-4y +3y =14

16-y = 14

-y= 14-16

-y=-2

y=2

.: x= 8-2y

x=8-2*2

x=8-4=4

.: the cost of one pencil = x = rs4 & the cost of one pen = rs2