Q: On a beach 50 people are wearing sunglasses and 35
people are wearing caps. Some people are wearing both sunglasses and
caps. If one of the people wearing a cap is selected at random, the
probability that this person is is also wearing sunglasses is 2/5. If instead, someone wearing sunglasses is selected at random, what is the probability that this person is also wearing a cap?
If 2/5 of the people wearing caps are also wearing sunglasses, that means that 35 * (2/5) = 14 people are wearing both caps and sunglasses.
There are a total of 50 people wearing sunglasses, so that means that 14/50 is the probability that a person wearing sunglasses is also wearing a cap. 14/50 = 7/25, so the answer is B.
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