Question 53252
A bag containing 5 white, 6 red and 7 blue balls. If 3 balls are selected at random what is the probability that they are all different colours? 
# of ways to select a group of three that has one white, one red, and one blue
is 5*6*7 or 210
# of groups of three balls of any color combination is 18C3=(18*17*16)/(1*2*3)
=816
Prob(3 of different colors)= 210/816= 0.257
Cheers,
Stan H.