Question

In a box there are 20 non-defective and some defective bulbs. If the probability that a bulb selected at random from the box found to be defective is 3/8 then, find the number of defective bulbs.

Answer 1

Let number of defective bulbs be ‘x’

Total number of bulbs = x + 20

⇒ 8x = 3x + 60

⇒ 5x = 60

⇒ x = 12

∴ No. of defective bulbs are = 12.