Answer:
To have no repeated digits, all four digits would have to be different, which is selecting without replacement. We could either compute 10 · 9 · 8 · 7, or notice that this is the same as the permutation 10P4 = 5040. Hence, there is a 50.4% chance that the 4-digit PIN has no repeated digits.
Step-by-step explanation:
correct me if im wrong..
