Question

In how many ways can 3 balls be selected from a box containing 2 red, 3 blue, 4 white and 5 black balls such that at least two selected balls are of the same colour? It is known that all the balls of a colour are identical.

Answer 1

Eish.

Draw three cases:
2 Red + one other color
2 Blue + one other color
2 Black + one other color.

Solve each individual one and add the ways together.

Answer 2

I seemed to have missed something.

2 Red + one any color (including red)
2 Blue + one any color (including blue)
2 Black + one any color (including black)