There are 6 red balls,8 blue balls and 7 green balls in a bag. If 5 are drawn with replacement, what is the probability at least three are red? Choose the correct option:
A) 312/16808
B) 312/16807
C) 312/16805
D) 312/16838
E) 312/16111
At least 3 reds means we get either : 3 red or 4 red or 5 red. And this is a case of replacement.   case 1 : 3 red balls : 6/21 x 6/21 x 6/21 x 15/21 x 15/21   case 2 : 4 red balls : 6/21 x 6/21 x 6/21 x 6/21 x 15/21   case 3 : 5 red balls : 6/21 x 6/21 x 6/21 x 6/21 x 6/21   Total probability = = (6/21 x 6/21 x 6/21 x 15/21 x 15/21)+(6/21 x 6/21 x 6/21 x 6/21 x (15 )/21)+ (6/21 x 6/21 x 6/21 x 6/21 x 6/21)   = 312/16807   Answer:312/16807
<result>B</result>
There are 6 red balls,8 blue balls and 7 green balls in a bag. If 5 are drawn with replacement, what is the probability at least three are red?