UPSC NDA Math Model Paper 1

The total number (N) of different 5 digit numbers that ean be formed using the five given digits =‌5P5=5!=120.
For a number to be divisible by 4 , the number formed by the last two digits must be a multiple of 4 . i.e. the last two digits must be 12,32,52 or 24→4 ways.
In each case, the number of different possibilities for the remaining three digits =‌3P3=3!=6 possibilities.
∴ The required probability =

n(A)

N

=

24

120

=

1

5

.