Question 338700
Four hundred people attending a party are each given a number, 1 to 400, for a door-prize drawing. One number is drawn at random to determine the winner. Find the probability that the number drawn: 
a. is 123 ::::::: 1/400
------------------------------ 

b. Consists of the same three digits.
There are 6 such numbers: 111,222,333
Probability = 3/400 
---------------------------- 

c. has two digits and ends in 9
1st digit: 3 ways: 1,2,3
2nd digit: 10 ways: 0-9
3rd digit: 1 way: 9
---
3*10*1 = 30/400 = 3/40 

d. does not contain an 8
1st digit: 3 ways: 1,2,3
2nd digit: 9 ways: 0,1,2,3,4,5,6,7,9  
3nd digit: 9 ways: 0,1,2,3,4,5,6,7.9
----
(3*81)/400 = 243/400


e. is an even number or greater than 390.
P(even) + P(>390) - P(even and >390)
1st: 1,2,3
2nd: any of 10
3rd: ends in 2,4,6,8,0
--
>390: 391-400
[3*10*5 + 10 - 5]/400 = 155/400
====================================
Cheers,
Stan H.