Question

find the common difference of the AP 1/p,1-p/p,1-2p/p...

Answer 1

as difference is denoted with d.
so, d = a2 - a1
         = 1-p/p - 1/p
          =1-p-1/p (comman lcm p)
            =0-p/p
            = -p/p
             = -1 
hence , comman difference is -1,

Answer 2

This is the right answer
D=-1
Enjoy
It was very easy