(a) If the order is relevant, then we need to calculate the number of permutations.
The number of permutations of n things chosen r at a time is found using:
In this case, we want to choose r = 3 colors, from a total of n = 4 colors. Using these values in the above formula, we get:
(b) If the order is not relevant, then we need to calculate the number of combinations.
The number of combinations of n things chosen r at a time is found using:
In this case, we want to choose r = 3 colors, from a total of n = 4 colors. Using these values in the above formula, we get: