10th Class Mathematics Probability Question Bank MCQs - Probability

A bag contains 24 balls of which x are red, \[\text{2x}\] are white and \[\text{3x}\] are blue. A ball is selected at random. What is the probability that the drawn ball is white or blue?

A) \[1/2\]

B) 2

C) \[5/6\]

D) \[7/12\]

Correct Answer: C

Solution :

[c] Total number of balls = 41

Now, \[x+2x+3x=24\Rightarrow 6x=24\Rightarrow x=4\]

\[\therefore \] Number of red balls \[=x=4,\]

Number of white balls \[=2x=8,\]

Number of blue balls \[=3x=12,\]

Total number of possible outcomes = 24

Let E be the event that the ball drawn is white or blue.

\[\therefore \] Number of outcomes fabourable to

\[\text{E}=\text{8}+\text{12}=\text{2}0\]

\[\therefore \,\,\,\,\,\,\,\,\,\,\,\,\,\,P(E)=\frac{20}{24}=\frac{5}{6}\]