1. Subscribertalzamir
    Art, not a Toil
    60.13N / 25.01E
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    19 Sep '11
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    45045
    31 Oct '11 08:39
    A straight wooden plank that doesn't bend at all is carried in a long that is 10 feet wide and seven feet high. At one point there is a T-crossing to a side passage five feet wide. How long can the plank be if it makes it through the crossing?
  2. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
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    52724
    01 Nov '11 08:24
    Originally posted by talzamir
    A straight wooden plank that doesn't bend at all is carried in a long that is 10 feet wide and seven feet high. At one point there is a T-crossing to a side passage five feet wide. How long can the plank be if it makes it through the crossing?
    Looks like 2 triangles 10x5 with the board being the length of the hypotenuse times two, or the square root of 125 times two= 22 feet and change. That would be if the board was carried in two dimensional space. I think the third dimension of 7 feet high, btw, the 5 foot wide corridor had an unspecified height so going by the exact wording, you can't strictly use the height so would have to treat it as a two dimensional passage.
  3. Subscribertalzamir
    Art, not a Toil
    60.13N / 25.01E
    Joined
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    01 Nov '11 09:071 edit
    Ah, sorry. This makes three variants:

    a. The side corridor is as high as the main corridor.
    b. The side corridor is extremely high.
    c. The side corridor has a generic height h that will remain as a parameter to the plank length.

    a. is as I had at first intended it but the others can be interesting too.