A bag contains 2 yellow, 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 answers:  A) 1/2  B) 10/21  C) 9/11  D) 7/11  E) 5/21
Explanation :   Total number of balls = 2 + 3 + 2= 
<gadget id="calculator">2 + 3 + 2</gadget>
<output>7</output>
7   Let S be the sample space.   n(S)= Total number of ways of drawing 2 balls out of 7 = 7C2   Let E = Event of drawing 2 balls , none of them is blue.   n(E) = Number of ways of drawing 2 balls , none of them is blue   = Number of ways of drawing 2 balls from the total 5 (=7-2) balls = 5C2   (âˆµ There are two blue balls in the total 7 balls. Total number of non-blue balls = 7 - 2= 
<gadget id="calculator">7 - 2</gadget>
<output>5</output>
5)   P(E)= n(E)/n(S)=5C2/7C2=(5X4 /2X1) /(7X6 /2X1)=5X4/7X6 =10/21   ANSWER IS 10/21
<result>B</result>
A bag contains 2 yellow, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?