Question

An urn contains 1 red ball, 2 green balls, and 4 blue balls. Three balls are randomly chosen from the urn. How many different color combinations are possible?
A.
6
B.
3
C.
5
D.
2

Answer 1

There are 6. Count nonnegative (r,g,b) with r≤1, g≤2, b≤4 and r+g+b=3. The possibilities:
BBB, GBB, GGB, RBB, RGB, RGG.
So answer A (6).