First of all, the upside down "U" means the intersection of sets, therefore (I don't know the Latex of symbol for the upside down "U" but it is called cap) A cap B is the number that appears in both sets. The only one that does this is 26, therefore A cap B is 26. So all you have to do is find the probability that 26 is chosen from the even numbers above 20 and less than 50. There are 14 even numbers, and 26 is one of them, so the probability that the number is in the set A cap B is \(\frac{1}{14}.\)
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