Question

A bag contains 7 red marbles, 2 blue marbles and 3 green marbles. If two marbles are drawn out of the bag, what is the exact probability that both marbles drawn will be blue?

Answer 1

Answer:

Therefore the probability of getting both  blue  marbles is $\frac{1}{66}$.

Step-by-step explanation:

Probability : The ratio of favorable outcomes to the total outcomes.

Given that a bag contains 7 marbles which are red in color, 2  marbles which are blue in color and 3  marbles which are green in color.

Total number of  marbles = (7+2+3) = 12

The probability of getting a blue on first drawn is

$=\frac{\textrm{No. of blue marbles}}{\textrm{Total number marbles}}$

$=\frac{2}{12}$

$=\frac16$

Now the number of blue marbles = (2-1)= 1 [ since 1 blue marbles is drawn]

Total number of  marbles = (12-1) =11

The probability of getting a blue marble on second drawn is

$=\frac{\textrm{No. of blue ball}}{\textrm{Total number ball}}$

$=\frac{1}{11}$

Therefore the probability of getting both  blue  marbles is

$=(\frac1 6 \times \frac1 {11})$

$=\frac{1}{66}$