Question 1195433
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If a prime is rolled on the first toss, then the required condition is already met.  The  numbers 2, 3, and 5 on a die are prime, so the probability that the required conditions are met after the first roll is 3/6 = 1/2.<br>
For the probability of the desired outcome to be increased on the second toss, the desired outcome must have NOT been met on the first toss.  So to the probability of 1/2 that the desired outcome is met on the first toss, we must add the probability that the condition was not met on the first toss (i.e., the number on the first toss was NOT prime) AND it was met on the second toss.<br>
The probability of NOT getting a prime on the first toss AND getting a 5 on the second toss is (1/2)(1/6) = 1/12.  So<br>
ANSWER: P(A ∪ C) = 1/2 + 1/12 = 7//12<br>