A thief steals an atm card and must randomly guess the correct five-digit pin code from a 4-key keypad. repetition of digits is allowed. what is the probability of a correct guess on the first try?
There are four possible digits for each of the five digits in the code. The total number of combinations is then 4^5, or 1024 different codes. Only one of them is correct, so the probability of getting it right is 1/1024
