Question

17. (i) A lot of 20 bulbs contain 4 defective ones. One bulb is drawn at random from the lot. What is the probability that this 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 this bulb is not defective ?

Answer 1

Heya !!!

Here is your answer.

Given :
Total number of bulbs = 20
Defective Bulbs = 4

Probability of getting a defective one = no. of defective Bulbs/total number of bulbs
= 4/20 = 1/5.

Now, if the bulb was not defective and was not replaced.
Then,
No defective Bulbs = 20-4 = 16.
Probability of getting a not defective bulb = 16/20 = 4/5

Hope It Helps

Answer 2

Heya !!!



Number of bulbs = 20


Possible outcomes = 20



Number of non - Defective bulbs = 20 -4 = 16

Number of defective bulbs = 4


Favourable outcomes = 4



(1) P(Getting a defective bulbs ) = Favourable outcomes/Possible outcomes = 4 / 20 = 1/5


And,


(2) P( Getting a non - Defective bulb) = 16/20 = 4/5








HOPE IT WILL HELP YOU...... :-)