Question

A bin contains 25 light bulbs, 5 of which are in good condition and will function for atleast 30 days, 10 of which are partially defective and will fail in the second day of use, and 10 of which are totally defective and will not light up. Given that a randomly chosen bulb initially lights, what is the probability it will still be working after one week?

Answer 1

5/25=as the bulbs which will lightup for more than a week =5 and total no of bulbs =25...=0.2