Friday Riddle

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nudgie
nudgie Member Posts: 1,478 Member
edited March 2014 in Colorectal Cancer #1
Remember NO GOOGLING or searching the Internet allowed and GOOD LUCK!!!!

LWS Inc recently came out with a series of three digit combination locks. The only problem is they were slightly defective. No combinations that started or ended in a zero would work, and combinations worked whether they were entered backwards or forwards. How many combinations would a cracker have to try before they were guaranteed to find one that works?

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  • AnneCan
    AnneCan Member Posts: 3,673 Member
    #2
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    Is the answer
    405?
  • PGLGreg
    PGLGreg Member Posts: 731
    #3
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    450
    Eliminating 100 starting with 0, another 90 ending with 0, and another 360 of the remaining 720 combinations whose first and last digits differ.

    --Greg

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