Problema Solution
In how many ways can you select a group of 5 red cards and 4 black cards from a deck containing 11 red cards and 9 black cards?
Answer provided by our tutors
we will assume that the order of cards doesn't matter:
11C5 × 9C4 = 11!/(5!(11 - 5)!) + 9!/(4!(11 - 4)!) = (7*8*9*10*11)/120 + (8*9)/24 = 465 ways.