Question 291630
If there were no restrictions, there would be 10000 possible choices from 0000 to 9999. 
Since the first number cannot be 3 then 3000-3999 are not available leaving only 9000 choices. 
The last digit is either even or odd and are evenly distributed so 4500 odds and 4500 evens. 
So that leaves 4500 available codes with the first number not 3 and the last digit not odd.