Saturday, 19 March 2011

One cream or two?

Answer to the last riddle: Separate the pile into two piles of 13 and 39, both with an unknown number of faceup cards. Now flip over the pile of 13. You now have the same number of faceup cards in both piles.

Didn't know what to make of that one eh? Hm. I had a hard time believing it too, had to try it out for myself. In fact, you can prove it algebraically (a cookie for whoever can show me this proof in the comments!)

Consider two identical cups, one half-full of tea, the other half-full of milk.  You take a teaspoon of milk from the milk cup and put it in the tea cup.  Then you take a spoonful out of the tea cup and put it in the milk cup. You take another spoonful out of the milk cup and into the tea cup, and one final spoonful from the tea cup to the milk cup. Now: is there more tea in the milk cup, or more milk in the tea cup? 
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38 comments:

  1. steve19 March 2011 at 01:36

    There is more milk in the tea cup.
    Unless it is half tea/half milk in each cup, then i suppose it is even..

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  2. Jay19 March 2011 at 01:37

    both remain the same? it doesn't say what spoon is full of when you place it back and forth.

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  3. Anonymous19 March 2011 at 02:49

    Two please!

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  4. Paranormal Explorer19 March 2011 at 03:18

    Algebra for yesterdays:
    Face up cards in deck of 13 cards = x
    Face down cards in deck of 13 = 13 - x
    Face up cards left in main deck = 13 - x
    Therefore flipping over the deck of 13 makes the 2 decks have an equal amount of face up cards :)


    As for todays riddle. Both will remain the same no matter how many spoonfuls you swap over. As the volume of each cup will stay the same as it started then any milk missing from the milk cup will have been replaced by tea and the volume of tea needed for that will have been replaced by milk.

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  5. DeadBeef19 March 2011 at 04:41

    hmmn, still thinking it over. I'll get back to you when I've solved it

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  6. Erika19 March 2011 at 05:30

    Am I really this dumb or does anyone else still find this confusing? xP

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  7. mehehehe19 March 2011 at 05:40

    =$

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  8. Coco19 March 2011 at 07:14

    shit, i´m horrible in this thinks..
    lol..

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  9. TheHarvester19 March 2011 at 07:19

    i think they remain the same

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  10. Justsayin'19 March 2011 at 07:33

    I'm going with milk on this one.

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  11. Meghan Moran19 March 2011 at 07:59

    I wanna say they both remain the same.

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  12. Fix PC Games Admin19 March 2011 at 09:40

    it's more chaotic that's for sure

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  13. RachiMaru19 March 2011 at 10:08

    i love this! ^ agreed

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  14. GADAFINY19 March 2011 at 10:40

    love your blog
    following and $upporting

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  15. Dudemeister19 March 2011 at 11:16

    There should be more milk in the tea cup. I think...

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  16. Lemmiwinks19 March 2011 at 11:28

    great background on this, bro!

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  17. G19 March 2011 at 11:55

    Both the same assuming the volumes in both cups are equal

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  18. Major Mack19 March 2011 at 12:08

    duhhhhh

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  19. Snapperz19 March 2011 at 12:17

    I want to say more tea in milk cup.

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  20. J. Reaper19 March 2011 at 12:39

    This blog is awesome! I love riddles! I'm gonna say there's a mixture in each of them since you kept mixing both of them.

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  21. Give Everything19 March 2011 at 13:22

    this blog is amazingly interesting! i can't do the things right now but as soon as i get home i will!

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  22. Justin19 March 2011 at 13:26

    There's more milk in the tea cup

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  23. LunaSihne19 March 2011 at 14:17

    They are the same.. I think.

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  24. ErikDesignwork19 March 2011 at 14:39

    More milk i tea cup i suppose.
    Im not sure though.
    Btw awesome blog! I love brain teasers, followed! ^^

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  25. Justin testing19 March 2011 at 15:58

    More milk in the teacup.

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  26. Anonymous19 March 2011 at 16:27

    loving the riddles man, keep it up

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  27. Con Queso19 March 2011 at 16:36

    You say half full, but what's the OTHER HALF filled with?! EH EH?!

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  28. ed19 March 2011 at 18:08

    the answer is the tea and milk is on the floor cause i spilled it

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  29. Big Unicorn19 March 2011 at 18:51

    I believe both would be equal.

    Supported.
    bigunicorn.blogspot.com

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  30. DanielM19 March 2011 at 19:57

    I'm not really sure. I would assume it would reach equilibrium at a certain point.

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  31. Trapper19 March 2011 at 23:04

    Where do you get this! They are tuff

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  32. Jesse Brooks20 March 2011 at 02:37

    There's more milk in the tea cup, as the first spoonful was undiluted, and each spoonful thereafter was progressively more dilute.

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  33. akrater20 March 2011 at 02:54

    The mixing ratios are equal. Calculated it. :D

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  34. Merlyy20 March 2011 at 04:00

    Equal dunno

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  35. SportsGuyBrandon20 March 2011 at 08:02

    I think Jay.CA is correct.

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  36. pv20 March 2011 at 10:32

    i thought they would;both remain the same

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  37. Jok3r20 March 2011 at 11:31

    Very nice ;)

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  38. jopjopjop20 March 2011 at 15:52

    it must be even?

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