hard · GMAT Quant
Coin X is fair and Coin Y lands heads with probability dfrac34. A coin is selected by an unknown rule. In a preliminary one-flip trial using that rule, the overall probability of heads was dfrac23. In the main trial, a coin is selected by the same rule and flipped until either 3 heads in total or 2 consecutive tails appear.
Given that the main trial stopped on the fifth flip and that flip was heads, what is the probability that Y was selected?
- dfrac917
- dfrac2743
- dfrac1829
- dfrac3251
- dfrac23
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