A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue? Choose the correct choice from the following choices:	A) 10 / 21	B) 11 / 21	C) 2 / 7	D) 5 / 7	E) 6 / 7
Total number of balls = (2 + 3 + 2)= 
<gadget id="calculator">(2 + 3 + 2)</gadget>
<output>7</output>
7.   Let S be the sample space.   Then, n(S)= Number of ways of drawing 2 balls out of 7   = 7C2 `   =(7 x 6)/(2 x 1)   = 21.   Let E = Event of drawing 2 balls, none of which is blue.   n(E)	= Number of ways of drawing 2 balls out of (2 + 3) balls.= 5C2 =	(5 x 4)/(2 x 1) = 10.   P(E) =	n(E)/n(S)	=	10/21   10 / 21nswer: 10 / 21.
<result>A</result>
A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?