Find the number of 4-digit numbers that can be formed using the digits 1, 2, 3, 4, 5 if no digit is repeated. How many of these will be even?
Total no. of digits possible for choosing =5
No. of places for which a digit has to be taken =4
As there is no repetition allowed;
⇒ No. of permutations = 
The number will be even when 2 and 4 are at one’s place.
The possibility of (2,4) at one’s place = 
Total number of even number = 120 × 0.4 = 48.
10