SN 1 QUESTIONS A certain type of push-button door lock requires you to enter a code before the lock opens. The lock has ten buttons numbered 0; 1; 2; 3; 4; 5; 6; 7; 8; 9. a) If you must choose an entry code that consists of a sequence of Six digits, with repeated numbers allowed, how many entry codes are possible? b) If you must choose an entry code that consists of a sequence of Six digits, with no repeated digits allowed, how many entry codes are possible?

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