Number of ways we can draw 6 chocolates drawn from 15 chocolates out of which 4 are blue, 5 are red and 6 are green if chocolates of the same colour are not distinguishable?
what i did was to use the coefficient method $x^6$ in the expansion of $(1+x+x^2..+x^6)(1+x+x^2+x^3+..+x^5)(1+x+x^2..+x^4)$. This should give the answer but i considered if there was a better approach for this problem rather than coefficient calculations ? I was looking if it was possible to solve it using Principle of inclusion and exclusion.
