There are 5 bags three of which each contains 4 white and 2 black balls, and remaining 2 bags each contains 1 white and 4 black ball; a white ball has been drawn, find the chance that it came from first group. Answers:
A) 2/7 B) 6/35 C) 8/25 D) 5/6 E) 3/5
Please go through my solution and suggest any mistake.   Chances of selecting a white ball from group 1: 2/3---------------------Chances of selecting a white ball from group 2: 1/5   Thus combined probability of section of white ball from group 1:   3/5 x 2/3 = 2/5   Thus combined probability of section of white ball from group 2:   2/5 x 1/5 = 2/25   Out of these chances, chance of occurrence of first case : (2/5) / (2/5 + 2/25) = 5/6   5/6
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There are 5 bags three of which each contains 4 white and 2 black balls, and remaining 2 bags each contains 1 white and 4 black ball; a white ball has been drawn, find the chance that it came from first group.