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Joined: 20 Feb 2017
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Re: The figure shown represents a board with 4 rows of pegs, and at the bo
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10 Mar 2022, 10:45
There are 4 rows.
the ball has 2 ways of moving-- to left or to right..
again when it falls in the peg in lower row, it can move to either direction- left or right ..
the final row again can have two ways
so TOTAL ways = 2*2*2 = 8 ways..
now ways the ball will fall in 1 = ways it will fall in 4..
and ways the ball will fall in 2 = ways it will fall in 3..
If you look at ways it can go in 1-
at every PEG, the ball has to move ONLY to left, so ways = 1*1*1 = 1 way
similarly in 4, the ball has to move ONLY to RIGHT so 1 way..
total ways for 3 and 2 = 8-2=6..
ways for each = 6/2 = 3..
prob of ball falling in 2 = 3/8
Answer: D