You are correct. To find the probability find the number of passwords that meet the requirement and put that over the total number of possibilities. There are 5 digits that meet the requirement of prime numbers or zero: 0, 2, 3, 5 and 7. So the number of five-digit passwords that meet this requirement is 5*5*5*5*5. Since we're choosing from 10 possible digits, the total number of five-digit passwords is 10*10*10*10*10. When you put (5*5*5*5*5)/(10*10*10*10*10), you can cancel out all of the 5's to get 1/(2*2*2*2*2) or 1/32 or
A.
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