Question: Fifty raffle tickets are numbered 1 through 50, and one of them is drawn at random. What is the probability that the number is a multiple of 5 or 7? Consider the following "solution": Since 10 tickets bear numbers that are multiples of 5 and since 7 tickets bear numbers that are multiples of 7, we conclude that the required probability is
10 + 7 = 17
50 50 50
What is wrong with this argument? What is the correct answer?