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Everything posted by rocdocmac

  1. Born on a Wednesday

    The probability that any one person selected at random was born on a Wednesday, is 0.1429 (~14 %). What is the probability that of any … (1) Seven persons chosen at random, exactly one was born on a Friday? (2) Five persons chosen at random, three were born on a Sunday? [Mr Moderator, if this question has appeared before, please remove it!]
  2. Cubicle Stack #2

    Suppose 27 identical cubes are glued together to form a cubical stack, as illustrated below. If one of the small cubes is omitted, four distinct shapes are possible. If two of the small cubes are omitted rather than just one, twenty-two distinct shapes are possible (see previously submitted Cubicle Stack at BrainDen.com). Now, if three of the cubelets are omitted, how many distinct shapes are possible?
  3. Cubicle Stack #2

  4. Cubicle Stack #2

  5. Cubicle Stack #2

  6. Cubicle Stack #2

  7. Born on a Wednesday

    @Molly Mae ...
  8. Cubicle Stack #2

    By the way, Thalia ...
  9. Whodunit?

    Oops, you're right! Sorry!
  10. Whodunit?

  11. Cubicle Stack #2

    Thalia, I'll check your current numbering later, but ...
  12. Whodunit?

    One more try then!
  13. Whodunit?

    Another go ...
  14. Cubicle Stack #2

    Nice approach! I'll wait for more solutions to come in before starting to comment.
  15. I'm Back

    Cavenglok: Welcome home where I only recently started!
  16. Whodunit?

    Back to square 1!
  17. Cubicle Stack

    Thank you Bonanova for your input! To all participants ... The 3-cubelet removal question has now been submitted as a separate new entry called "Cubicle Stack #2" since the thread sort of "got lost" in the original Cubicle Stack discussion after having been solved!
  18. A simple integration paradox?

    ∫1/(2x) = ½ln|x| + c. ln|2x| = ln|x| + ln(2), where ln(2) is a constant