A box containes 1 red ball, 2 green ball and 4 blue balls?
What are the various probability if one ball is drwan at random?
 Number of all possible outcome in drawing the balls =no of balls in the box = 7 .

Probability that the ball drawn in red = $1/7$

Probability that the ball drawn in green = $2/7$

Probability that the ball drawn in blue = $4/7$