Question 1089626: You roll two six-sided dice. What is the probability that the sum is odd or a multiple of 5? Round the answer to the nearest tenth of a percent.
Answer by reviewermath(1029)   (Show Source):
You can put this solution on YOUR website! You roll two six-sided dice. What is the probability that the sum is odd or a multiple of 5? Round the answer to the nearest tenth of a percent.
Solution:
Let A = event that the sum is odd
B = event that the sum is a multiple of 5
A = {(1,2), (1,4), (1,6), (2, 1), (2,3), (2,5), (3,2), (3,4), (3,6), (4,1), (4,3), (4,5), (5,2), (5,4), (5,6), (6,1), (6,3), (6,5)}
There are 18 elements in set A
B = {(1,4), (2,3), (3,2), (4,1), (4,6), (5,5), (6,4)}
There are 7 elements in set B
A AND B = {(1,4), (2,3), (3,2), (4,1)}
There are 4 elements in set A AND B (intersection)
Since there are  = 36 possible outcomes when two six-sided dice are rolled, then P(A) = 18/36, P(B) = 7/36, and P(A and B) = 4/36.
P(A OR B) = P(A) + P(B) - P(A and B)
= (18/36) + (7/36) - (4/36) = 21/36 or  percent
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