When a pair of dice is thrown the sample space consists
{(1, 1) (1, 2) .......... (1, 6)
(2, 1,) (2, 2,)......... (2, 6)
.... ..... ........
... ... ... ...
(6, 1), (6, 2) ........ (6, 6)}
Note that (1, 2) and (2, 1) are considered as separate points to make each outcome as equally likely. To get a total of ‘8’, favourable outcomes are, (2, 6) (3, 5) (4, 4) (5, 3) and (6, 2).
Hence required probability = 5/36