Q. You have the assignment of designing colour codes for different parts. Three colors are to be used on each part, but a combination of three colours used for one part cannot be rearranged and used to identify a different part. this means that is a green, yellow and violet were used to identify a camshaft, yellow, violet and green (or any other combination of these three colours) could not be used to identify a pinion gear. If there are 35 combinations, explain how many colours were available?