(1) Find the possible values of Y:

After the decimal point, any of the 10 digits can appear, so Y{0,1,,9}.


(2) Find the PMF of Y:

Each digit has a 110 chance of appearing.

PY(y)={110y{0,1,,9}0otherwise

(3) Find the CDF of Y:

FY(y)={0y<0110(y+1)0y919<y