Total no. of possible outcomes = 20 {20 bulbs}

**(i) E ⟶ be event of getting defective bulb.**

No. of favourable outcomes = 4 {4 defective bulbs}

Probability, P(E) = (No.of favorable outcomes)/(Total no.of possible outcomes) = 4/20 = 1/5

(ii) Bulb drawn in is not detective & is not replaced remaining bulbs = 15 good + 4 bad bulbs = 19

Total no. of possible outcomes = 19

**E ⟶ be event of getting defective**

No. of favorable outcomes = 15 (15 good bulbs)

P(E) = 15/19