Question

Two balls are drawn at random from a bag containing 1 red, 4 green and 2 blue balls. What is the probability that none of the balls drawn is blue?

• A.
• B.
• C.
• D. None of these

Answer 1

The correct option is B

Total number of balls = (1 + 4 + 2) = 7.

Let S be the sample space.

Then, n(S) = Number of ways of drawing 2 balls out of 7

= ${}^7{C}_2$

= 21.

Let E = Event of drawing 2 balls, none of which is blue.

$\therefore$ n(E) = Number of ways of drawing 2 balls out of (1 + 4) balls.

= ${}^5{C}_2$ =10

P(E) = $\frac{10}{21}$.