A box contains 4 red balls and 6 black balls. Three balls

A box contains 4 red balls and 6 black balls. Three balls are selected randomly from the box one after another, without replacement. The probability that the selected set contains one, red ball and two black balls is

Given :		Red		Black
		4		6

Selection will be RBB or BBR of BRB

Probability of selecting RBB =		4	×	6	×	5
		10		9		8

Probability of selecting BBR =		6	×	5	×	4
		10		9		8

Probability of selecting BRB =		6	×	4	×	5
		10		9		8

P (Red = 1) = sum of above three probabilities = 0.5