There is a total of 84 marbles in a box, each of which is red, green, blue, or white. If one marble is drawn from the box at random, the probability that it will be white is 1/4 and the probability that it will be green is 2/7. What is the probability that the marble will be either red or blue?  Pick:	A) 3/7	B) 11/14	C) 13/28	D) 19/28	E) 29/42
P(red or blue) = 1 - P(white) - P(green) = 28/28 - 7/28 - 8/28 = 13/28   The answer is 13/28.
<result>C</result>
There is a total of 84 marbles in a box, each of which is red, green, blue, or white. If one marble is drawn from the box at random, the probability that it will be white is 1/4 and the probability that it will be green is 2/7. What is the probability that the marble will be either red or blue?