two dice are rolled.find the probability of obtaining tha:A sum of 5

Question

two dice are rolled. find the probability of obtaining:

A sum of 5.

Answer 1

There are 36 possible results of throwing two dice, but since (a,b) is the same combination as (b,a) there are only 21 combinations, including doubles (1,1), (2,2), etc. Of these the sum of 5 is only possible with 1+4 and 2+3. The table marks with X all the possible combinations of throws. So only 2 out of 21 produce a sum of 5. Therefore the probability of a sum of 5 is 2/21.

	1	2	3	4	5	6
1	X	X	X	X	X	X
2		X	X	X	X	X
3			X	X	X	X
4				X	X	X
5					X	X
6						X