Question

A box contains 12 light bulbs, of which 5 are defective. All bulbs look alike and have equal

probability of being chosen. Two lights are selected with replacement. What is the
probability that at least one is defective?

Please help

Answer 1

Answer: 95/144


Step-by-step explanation:

There are 12 light bulbs.
There are 5 defective bulbs.
There are 7 not defective bulbs.

P (at least one defective) = first one defective or second one defective or both defective.

P (at least one defective) = (5/12)(7/12) + (7/12)(5/12) + (5/12)(5/12) = 95/144