Question

There are 15 balls in a box: 8 balls are green, 4 are blue and 3 are white. Then 1 green and 1 blue balls are taken from the box and put away. What is the probability that a blue ball is selected at random from the box?

Answer 1

Answer:

Total number of balls = 15

Balls after removing 1 blue and 1 green box = 13

So

green balls = 7

Blue balls = 3

White = 3

Possible number of outcome = 13

Favourable outcome (blue balls) = 3

Probability =

$\frac{favourable \: outcome}{all \: possible \: outcome}$

$probability \: = \frac{3}{13}$