two different dice are thrown at the same time. find the probability that the sum of the two numbers appearing on the top of the dice is 7.
Elementary events associated to the random experiment of throwing two dice are:
∴ Total number of outcomes = 36
Let A be the event of getting the sum of numbers appearing on the dice as 7.
Elementary events favourable to the event A are (1, 6), (2, 5), (3, 4), (4, 3), (5, 2) and (6, 1).
Favourable number of outcomes = 6
Thus, the required probability is .