A bag contains 25 balls such as 10 balls are red, 7 are white and 8 are blue. What is the minimum number of balls that must be picked up from the bag blindfolded (without replacing any of it) to be assured of picking at least one ball of each colour?
(a) 10
(b) 18
(c) 63
(d) 35
I got this question in exam.
My question comes from Counting topic in chapter Counting of Discrete Mathematics