Question 1162752
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In all, there are 3 + 4 + 2 + 1 = 10 marbles initially in the basket.


(a)  What is the probability that he chooses either a red or {{{highlight(cross(a))}}} <U>the</U> black marble?


     P = P(a read) + P(the black) = {{{3/10}}} + {{{1/10}}} = {{{4/10}}} = 0.4.




(b)  P = P(1st is a red)*P(2nd is a white) + P(1st is a white)*(P(2nd is a red) = {{{(3/10)*(2/9)}}} + {{{(2/10)*(3/9)}}} = {{{6/90 + 6/90}}} = {{{12/90}}} = {{{2/15}}}.




(c)  I can not answer this question,

     because from the post, it is unclear, if it relates to choosing/pickaping one or two marbles.


     While experiment is described accurately in cases (a) and (b), it is not described accurately in case (c).
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