An urn contains 5 red and 2 green balls. A ball is drawn at random from the urn. If the drawn ball is green, then a red ball is added to the urn and if the drawn ball is red, then a green ball is added to the urn; the original ball is not returned to the urn. Now, a second ball is drawn at random from it. The probability that the second ball is red, is:-
Conditional Probability -
Let A and B be any two events such that or
n(B) = 0 or P(B) = 0 then denotes the conditional probability of occurrence of event A when B has already occured
-Independent events -
If A and B are independent events then probability of occurrence of A is not affected by occurrence or non occurrence of event B.
and
so
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Let, A: Event of drawing a red ball and placing a green ball in the bag.
B: Event of drawing a green ball and placing a red ball in the bag.
c: Event of drawing a red ball in the second draw.