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Must be a typo.
15/47=31.9
15/46=32.6
31.9+32.6=64.5
Am I missing something?

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Yes you are missing something, you are doing the math wrong, you cannot simply add the probabities together. The equation looks like this...you basically have to figure out the probability of the event not happnening and then take that probabilty and substract it from 1.
(32/47) x (31/46) = .4588,
1 - .4588 = .5412 which is 54.1%