Answer:
[tex]\dfrac1{126}[/tex]
Step-by-step explanation:
9 all possible digits (1, 2, 3, 3, 4, 5, 6, 7, 8, 9)
4 digits and no digits repeated so
9•8•7•6 - number of all possible codes
4 even digits (2, 4, 6, 8)
4 digits and no digits repeated so
4•3•2•1 - number of all codes wich consists of all even digits
What is the probability that the lock code consists of all even didgit:
[tex]\dfrac{4\cdot3\cdot2\cdot1}{9\cdot8\cdot7\cdot6}=\dfrac{1\cdot1\cdot1\cdot1}{9\cdot2\cdot7\cdot1}=\dfrac1{126}[/tex]
