Question

the price of a pen is 9 rupees more than the price of a pencil price of a book is 8 rupees more than the price of a pen total price of 12 pens and 12 pencills is equal to the price of 9 books find the price of pen pencill and book

Answer 1

Here you didn't tell how many books
So I took from another question ie 9 books
one pencil = x
One pen = x + 9
one book = x + 9 + 8 = x + 17
12 pens = 12x + 108
12pencils = 12x
9 books = 9 (x+17) = 9x + 153
12x + 108 + 12x = 9x + 153
15x = 45
x = 3
Pencil = Rs 3
Book = 3 + 17 = 20
Pen = 3 + 9 = 12

Answer 2

let price of pencil be x
price of pen=x+9
price of book= x+9+8= x+17

now price of12 pen + price of 12 pencil= price of 9 books
12(x+9)+12×x=9(x+17)
12x+108+12x=9x+153
24x-9x=153-108
15x=45
x=45/15= 3 rs

so price of pencil= 3rs
price of pen= 3+9=12rs
price of book=3+9+8=20rs