American Express Business Travel uses a nine-letter record locator number (RLN) for each client's trip (e.g. KEZLFSRQM). (a) How many different RLNs can be created using capital letters (A-Z)? Number of RLNS (b) What if it allows any mixture of capital letters (A-Z) and digits (0-8)? Number of RUN (c) What If it allows capital letters and digits but excludes the digits 0 and 1 and the letters and I because they look too much alike? Number of R