Alocker combination has three nonzero digits, with no digit repeated. if the first two digits are odd, what is the probability that the third digit is also odd?

If you can get this using evens,
The digits are probablly  1 to 9, then the even is 2,4,6,8 and the odd are 1,3,5,7,9. 

Prodd(ways/choices)=5/(2+5)

So, Using odd numbers, The digits are likely to be 1-9, so the odds are 1,3,5,7,9. Look at the middle number, 5⇒6+3 (because of odds not evens that use 2). 6,7,8,9. 5/9 is your answer.

Maybe this helped and if it did then yw. :D