Total number of exhaustive events =63=216.
Now in the case of die 2>1 (i.e. second number is larger than first number). Let second number is i(i>1) then the first number can be selected by / - 1 ways and third number by 6−i ways so the number of ways in which three numbers can be choosen are (i−1)×1×(6−i) So, the total number of favourable cases are
=\sum_{i=2}^{5}(i-1)(6-i)=20
Hence, required probability is =21620=545