❔ A bag contains 19 red balls and 19 black balls. Two balls are removed at a time repeatedly and discarded if they are of the same colour, but if they are different, black ball is discarded and red ball is returned to the bag. The probability that this process will terminate with one red ball is
a) 1
b) 1/21
c) 0
d) 0.5
Answer is 1:
there are 4 possible combinations of balls:
RR -- discard
RB -- keep red discard black
BR -- keep red discard black
BB -- discard
repeated combination comes for each above (RR,RB,BR,BB) then,
due odd number of balls:
the last combination in the bag is RB.
a) 1
b) 1/21
c) 0
d) 0.5
Answer is 1:
there are 4 possible combinations of balls:
RR -- discard
RB -- keep red discard black
BR -- keep red discard black
BB -- discard
repeated combination comes for each above (RR,RB,BR,BB) then,
due odd number of balls:
the last combination in the bag is RB.
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