math
posted by daron on .
Mrs.fairweather has placed 10 tiles in a bag.one are red,some are blue,and some are yellow.how many different combination of the colors are possible?

Since it asks for "how many different combinations of the colours are possible"
we are merely interested in the number of subsets of the 4 colours.
number of subsets are 2^4 = 16
but that would include the one case of not choosing any, so
I would say there are 15 choices of colours
The answer would be the same if there were 200 tiles, as long as we have some of each of the colours