Question

The ratio of cost of a pencil to that of a pen is 4:5 . If the cost of a note book is rs.15, find the cost of a pencil.​

Answer 1

let the cost of pencil and pen in the ratio 2:3 be 2x and 3x respectively and cost of pen and a notebook in the ratio 4:5 be 4y and 5y.

5=15

=> y= 15/5

=> y= 3

I. e cost of pen = 4y

= 4×3

= 12

Now,

3x= 12 ( cost of pen )

=> x= 4

So, cost of pencil= 4×2=8