A thief steals an ATM card and must randomly guess the correct four​-digit pin code from a 6​-key keypad. Repetition of digits is allowed. What is the probability of a correct guess on the first​ try?

Answer 1

probability of guessing the first digit right is 1/6,

probability of guessing the 2nd digit right is 1/6,

probability of guessing the 3rd digit right is 1/6,

probability of guessing the 4th digit right is 1/6,

so it would be: (1/6 )*(1/6 )*(1/6 )*(1/6 )= 1/(6^4)

Answer 2

number of possible codes is 9^5=59049

probability of guessing right on the first try is 1/59049.