Chapter 8.4, Problem 33MS

Car care. A burglar wishes to break into a car that has a security system. There are five buttons (marked 1 through 5) to disarm the system, and he knows the code is a three-digit number like 253 or 422. How many possible security codes are there? Knowing this number of combinations, the burglar fears that he will enter the wrong number first—thus tripping the alarm (which everyo ne just ignores). So he writes down his first 20 guesses and then enters his next guess. Does this strategy improve his chances of success? Explain.