Given the diagram shown at the right, as labeled in feet with B-
C-D collinear. A chain is laid
along the hypotenuse in each
triangle. Find the total length of
the chain.
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The probability would be 1/30.

The probability that Mike goes first is 1/6, since each person has an equal chance of being chosen first.  After Mike goes, Jim has a 1/5 chance to go next, since Mike has already gone.  The probability is then

1/6(1/5) = 1/30.