Question

If there are 2 yellow flags, 4 red flags, and 3 blue flags, how many combinations are possible

Answer 1

The question, as written, is a little vague.

There are 2*4*3=24 possible arrangement of three distinct flag colors.
If colors can repeat, and the position of the flags is considered important, then there are 9*8*7=504 distinct arrangements of three flags.
If you are interested in counting the number of arrangements of all nine flags, there are 9!=362880 arrangements.