If nCk represents the number of ways k parts can be chosen from a pool of n, the probability of interest is the complement of the probability of selecting all good parts. 1 - (167C3)/(170C3) = 42,085/804,440 ≈ 0.0523
the question is: why should ppl answer your questions correctly and help you when you dont answer thier questions and help them when they need it? why help some one who wont help you?