Question

You need to have a password with 5 letters followed by 2 odd digits between 0 and 9, inclusive. If the characters and digits cannot be used more than once, how many choices do you have for your password?

Answer 1

5 letters (26 choices without replacement)
26*25*24*23*22

2 odd digits (5 choices w/o replacement)
5*4

26*25*24*23*22*5*4
= 157,872,000 choices