Probability word problem

Question

A bag contains 8 red balls, 3 white balls, and 9 blue balls. If 3 balls are randomly chosen, what is the probability of getting 2 red balls and 1 white ball?

 

i'm not sure how to do this question. i would know how to do it if 2 red balls were chosen, or 1 white ball, etc. but not both :/

Answer 1

Once a ball is drawn the total number of balls decreases by one just as removing one red would decrease the number of red balls. There are twenty balls total, 8 red and 3 white; if we want two reds and a white:

 

 

(8/20)*(7/19)*(3/18) = 168/6840 = 0.02456..