Question

The cost of 4 pens and 8 pencils is rupees 84. If pen cost rupees 12 than pencil find price of one pen and pencil

Answer 1

pens= 4
pencils=8
pencil cost=x
pen cost = 12+x
total cost = x+x+x+x+x+x+x+x+x+12+x+12+x+12+x+12
                =9x+12+x+12+x+12+x+12
                = 9x+48+3x
                =12x+48
12x+48 = 84
12x=84-48
       =36
x=36/12 = 3
pencil cost = 3
pen cost=3*12 = 15

Answer 2

let,
the cost of pencil = x
then , the cost of pen = 12 + x
according to the question,
4( 12 + x) + 8x = 84
48 + 4x + 8x = 84
48 + 12 x = 84
12x = 84 - 48
12 x = 36
x = 3
now, cost of pencil = 3
cost of pen = (12 + x) = 12+ 3 = 15