maths
posted by keith on .
A die is thrown twice. Find the probability that the number obtained in the first throw is smaller than that in the second throw.

just add them up, considering the 1st throw:
6: 0
5: 1/6
4: 2/6
...
1: 5/6
sum: (1/6)(15/6) = 5/12
since the chance of throwing each of the 1st numbers is 1/6.