fom wrote: >William Elliot wrote: >>G Patel wrote: >> >>> Is it 20 choose 10 or do I have to divide by 2? >>> >> What's it? > >What do you mean by picking teams? Combinations are without >regard to order, > >captains will try to make the best pick at each opportunity >to choose... > >20*18*16*14*12*10*8*6*4*2 > >19*17*15*13*11*9*7*5*3*1
In the context of this problem, the only interest is in determining the number of possible results for the two teams, not in the mechanism by which the selection was performed.
In particular, the order of selecting people doesn't matter.
The intent of the problem is to find the number of possible partitions of a 20-element subset into two 10-element subsets.