Multiple choice

A box contains 10 screws, 3 of which are defective. Two screws are drawn at random with replacement. The probability that none of the two screws is defective will be

  1. 100%

  2. 50%

  3. 49%

  4. None of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Since drawing is done with replacement, the probability of selecting a non-defective screw in a single draw is 7/10. For two independent draws, the probability that neither is defective is (7/10) * (7/10) = 49/100, which is 49%.