Question

ype-ll Questions:
[3 Mark each]
7) (i) A lot of 30 bulbs contains 5 defective bulbs. One bulb is drawn at random from the
lot. What is the probability that the bulb is defective?
(ii) Suppose the bulb drawn in (i) is not defective and is not replaced. Now one bulb is
drawn at random from the rest. What is the probability that the bulb is not defective?​

Answer 1

Answer:

• Good bulbs = 25 – 5 = 20

P (good bulb) = 20/25 = 4/5.

• One non defective bulb is drawn in

(i) then the total numbers of bulb left is 19 numbers of events = 19

Favourable numbers of events = 19 - 4 = 15

Probability that the bulb is not defective = 15/19