Question

Suppose a box contains 3 defective light bulbs and 12 good bulbs. two bulbs are chosen from the box without replacement. find the probability that one of the bulbs drawn is good and one is defective.

Answer 1

The probability that the bulb is good is 12/15.
Since we have taken 1 item out the remaining total is now 14, so the probability of getting a defective bulb is now 3/14.
Now you multiply the probabilities together to get (12/15)(3/14)=(4/5)(3/14)=12/70=6/35