We need to guess 5 letter among alphabet of A~Z. What is probability of correctly guessing 2, 3, 5 letters respectively. given they are all upper letters and alphabetic order is preserved (no Z comes before any letter, or no A comes after any letter etc). I know mentioned it before, but I really appreciate providing any way of solving the problem. I really need to solve the problem.. please help!!!!!!!!!!!! Thanks in advance for you thoughts shared.