Question 1178839
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The probability that all 4 are good is  P = {{{(1-0.11)^4}}} = {{{0.89^4}}} = 0.6274   (rounded).



The probability that at least one is defective is the COMPLEMENT to it


    P' = 1 - 0.6274 = 0.3726.      <U>ANSWER</U>
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Solved.