If strings of 3 letters are formed using the letters R, S, T, U, V, W how many such words are possible for each of the following conditions: (a) No letter can be repeated in a word. Your answer is: (b) Each word must begin with the letter S and letters can be repeated. Your answer is: (c) The letter T must be at the end and letters can be repeated. Your answer is: (d) The third letter must be a consonant and letters can be repeated. Your answer is: