Sample space = {00,10,11,...99} = 100 Total outcomes
from 00 to 99 you can form 100 numbers with 2 digits (including 00). So any 2 digit number could be written T (tens) and U (unit) → TU
T can take any value from 0 to 9, then there are 10 ways to choose T U can take any value from 0 to 9 EXCEPT 5, then there are 9 ways to choose U. Then we can select TU in 10 x 9 = 90 ways Favorable outcome ={90} P(2 digits NOT ending in 5) = 90/100 = 0.9