Gmat Prep Probability
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Two out of the four expressions are chosen at random:
4c2
4!/2!(4-2)! = 6
So you have 6 possible ways to choose 2 of the expressions.
Only 1 way meets the requirements: (x+y)(x-y)
So you the probability would be 1/6
4c2
4!/2!(4-2)! = 6
So you have 6 possible ways to choose 2 of the expressions.
Only 1 way meets the requirements: (x+y)(x-y)
So you the probability would be 1/6