Question 505240
A quality control inspector samples 5 computer chips from a box containing 11 computer chips. If the box contains 2 defective chips, in how many ways can he select a sample so that both defective chips are selected? 
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# of ways to select 2 defective = 2C2 = 1
# of ways to select 3 other = 9C3 = 84
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Ans: # of ways to pick 5 chips with 2 defective: 1*84 = 84
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Cheers,
Stan H.