[face=Verdana]A large cube 10cm on a side is composed of smaller cubes 1 cm on a side. The large cube is printed red on its outside surfaces and then all the cubes are mixed in a drum. If one cube is selected randomly, which of the following is the approximate probability that the cube will have at least one red face?
The answer is ( 1:2 ). Can anyone explain it for me?[/face]
是488:1000. close to 1:2 10x10x10=1000. so there will be 1000 small cubes (1x1x1) (10-2)x(10-2)x(10-2) = 512 so there will be 512 small cubes without one red face.
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发表于 2003-11-27 01:50:00
