Question

A thief steals an atm card and must randomly guess the correct three​-digit pin code from a 7​-key keypad. repetition of digits is allowed. what is the probability of a correct guess on the first

Answer 1

First digit: 1 digit out of 7 total keys = 1/7
Second digit: 1 digit out of 7 total keys = 1/7
Third digit: 1 digit out of 7 total keys = 1/7

First AND Second AND Third
1/7 x 1/7 x 1/7 = 1/343