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Red cherry after moving one between bowls

Question

Bowl AA holds 44 red and 55 purple cherries; bowl BB holds 66 red and 33 purple. Jenny moves one cherry chosen at random from AA into BB, and then eats a cherry chosen at random from BB. What is the probability that the cherry she eats is red?

Short answer

2945\tfrac{29}{45}. Bowl BB now has 1010 cherries, one of which came from AA. The eaten cherry is the transferred one with probability 110\tfrac1{10} (red with chance 49\tfrac49) and an original BB cherry otherwise (red with chance 23\tfrac23): 110⋅49+910⋅23=2945\tfrac1{10}\cdot\tfrac49+\tfrac9{10}\cdot\tfrac23=\tfrac{29}{45}.

Adapted from QuantQuestions.io; question and answer rewritten by SelfMadeQuant.com.

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