An urn contains 10 white balls and 10 red balls. Ten balls are drawn from the urn without replacement.
a. Find the probability that the fourth ball is red given that the first ball is red.
b. Find the probability the third ball is red given at least one of the first two balls is red.
c. Find the expected number of white balls drawn
d. Is the event that the last ball is red independent of the event that the first two balls are of different colors?
a.Pr(fourth ball is red| first ball is red) = 9/19
b. Pr(third ball is red|at least one of first two are red) = Pr(third ball is red|both red) + Pr(third red|first red) + Pr(third red|second red) = 9/19 + 9/19 -7/17
c. 10*0.5 = 5
d. Stuck here.