6.(iii)    Two dice are thrown. The events A, B and C are as follows:

            A: getting an even number on the first die.

            B: getting an odd number on the first die. 

            C: getting the sum of the numbers on the dice  \leq 5.

            Describe the events

            (iii) A or B

Answers (1)
H Harsh Kankaria

Sample space when two dice are thrown:

S = {(x,y): 1 \leq x,y \leq 6}

A: getting an even number on the first die = {(a,b): a \in {2,4,6} and 1 \leq b \leq 6}

 = {(2, 1), (2,2), (2,3), (2,4), (2,5), (2,6), (4,1), (4,2), (4,3), (4,4), (4,5), (4,6), (6,1), (6,2), (6,3), (6,4), (6,5), (6,6)}

B: getting an odd number on the first die = {(a,b): a \in {1,3,5} and 1 \leq b \leq 6}

 = {(1,1), (1,2), (1,3), (1,4), (1,5), (1,6), (3,1), (3,2), (3,3), (3,4), (3,5), (3,6), (5,1), (5,2), (5,3), (5,4), (5,5), (5,6)}

(iii) A or B = A \cup B = {(1,1), (1,2) .... (1,6), (3,1), (3,2).... (3,6), (5,1), (5,2)..... (5,6), (2,1), (2,2)..... (2,6), (4,1), (4,2)..... (4,6), (6,1), (6,2)..... (6,6)} = S 

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