Hmm.
Suppose there are 1,000,000 items, 700,000 of which are good, 300,000 of which are defective.
The probability that the first one you choose is good is 700,000/1,000,000 = 0.7.
You now have 699,999 good ones left out of a total of 999,999, so the probability of selecting a second good one is 699,999/999,999 ≈ 0.6999997
You now have 699,998 good ones left out of a total of 999,998, so the probability of selecting a third good one is 699,998/999,998 ≈ 0.6999994
The overall probability is therefore 0.7*0.6999997*0.6999994 ≈ 0.343 ≈ 0.73
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