<PRE><B>Question 179690</B>
6.) What is the probability that a random 2-digit number (00-99) does not end in 5?
----
There are 100 numbers if you include 00.
# that do not end in 5?
10 ways to pick the tens digit
9 ways to pick the ones digit
So, 10*9 = 90 ways to have a two-digit number not ending in 5
---
Therefore P(2-digit not ending in 5) = 90/100 = 9/10
============================================================

8.) A clerk has 4 different letters that need to go in 4 different envelopes. What is the probability that all 4 letters are placed in the correct envelopes? 
--
# of possible arrangements: 4! = 24
# of correct arrangements: 1
---
Probability of getting the right arrangement: 1/24
=====================================================
Cheers,
Stan H.</PRE>