How many even numbers less than 500 can be formed using the digits 1,2,3,4,5? Each digit can only be used once.
1 Answer
Explanation:
The number must end with

Three digit numbers: Having chosen
#2# or#4# for the last digit, there are#3# admissible possibilities for the first digit, namely#1# ,#3# or whichever of#2# or#4# is left. Finally, any of the#3# remaining digits can be used for the middle digit. So there are#2xx3xx3 = 18# possible#3# digit numbers. 
Two digit numbers: Having chosen
#2# or#4# for the last digit, there are#4# possibilities for the first digit, so a total of#2xx4 = 8# possibly#2# digit numbers. 
One digit numbers:
#2# or#4# , which makes#2# possibilities.
So there are a total of