Question

A box contains 150 bulbs out of which 15 are defective. It is not possible to just look at a bulb and tell whether or not it is defective. One bulb is taken out at random from this box. Calculate the probability that the bulb taken out is a good one.

Answer 1

Total number of possible outcomes = 150 

Out of 150 bulbs, 15 are defective 

Number of bulbs which are good = 150 – 15 = 135 

P(taking out a good bulb) = `135/150 = 9/10`