Rework problem 17 from section 1.4 of your text, involving a product code. Assume that product codes are formed from the letters U, T, Y, and R, and consist of 6 not necessarily distinct letters arranged one after the other. For example, UUYRRR is a product code. (1) How many different product codes are there? 4096 (2) How many different product codes do not contain Y? 729 (3) How many different product codes contain exactly one R? 162