9514 1404 393
Answer:
a) 1,544,804,416
b) 52,523,350,144
c) 34
Explanation:
(a) Each character position can be any of 24 letters or 10 digits, so any of 34 characters. The number of possible characters sets increases by a factor of 34 for each added character. A six-character plate will have ...
34^6 = 1,544,804,416 . . . possibilities
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(b) 34^7 = 52,523,350,144 . . . possibilities
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(c) 34^7/34^6 = 34 . . . times as many