3. An experiment involves rolling a pair of dice and recording the numbers that come up. Describe the following events:
C: the sum is at least and a multiple of
Sample space when a die is rolled:
S = {1, 2, 3, 4, 5, 6}
Let E = Event of rolling a pair of dice (= Event that a die is rolled twice!) [6x6 = 36 possible outcomes]
E = [ {(x,y): x,y S } ] = {(1,1), (1,2)...(1,6),(2,1).....(6,5),(6,6)}
Now,
C: the sum is at least 7 and a multiple of 3
The sum can only be 9 or 12.
C = [ {(a,b): (a,b) E, a+b>6 & a+b = 3k, k I} ]= {(3,6), (6,3), (5, 4), (4,5), (6,6)}