# Moderate Probability Solved QuestionAptitude Discussion

 Q. A bag contains 2 red, 3 green and 2 blue balls are to be drawn randomly. What is the probability that the balls drawn contain no blue ball?
 ✖ A. 5/7 ✔ B. 10/21 ✖ C. 2/7 ✖ D. 11/21

Solution:
Option(B) is correct

2 balls can be drawn in the following ways:

1 red, 1 green or 2 red or 2 green

Required probability:

$=\left(\dfrac{^2C_1\times ^3C_1}{^7C_2}\right)+\dfrac{^2C_2}{^7C_2}+\dfrac{^3C_2}{^7C_2}$

$=\dfrac{6}{21}+\dfrac{1}{21}+\dfrac{3}{21}$

$=\dfrac{10}{21}$

## (1) Comment(s)

VTG
()

there is no mention of 2 balls drawn in the question.Admin please correct.Thank you