Defective roll probability

[jcnissi]

There are 15 rolls of film in a box and 3 are defective. Two rolls are to be selected, one after the other. What is the probability of selecting a defective roll followed by another defective roll?

[Rahul@gurome]

There are 15 rolls of film in a box and 3 are defective. Two rolls are to be selected, one after the other. What is the probability of selecting a defective roll followed by another defective roll?

Defective number of rolls = 3
Total number of rolls = 15
Probability of selecting a defective roll out of 15 = 3/15

Now, Defective number of rolls = 2
Total number of rolls = 14
Probability of selecting a defective roll out of 14 = 2/14

Required probability = (3/15)*(2/14) = 1/35

[hoji]

Rahul, i think 3 are defective of those 15 rolls, so my solution is:
probability of coming the first roll out as a defective is 3/15 and consequently the second one`s is 2/14 and taking them together, it is like 3/15*2/14=1/35
what do you say?

[Rahul@gurome]

Rahul, i think 3 are defective of those 15 rolls, so my solution is:
probability of coming the first roll out as a defective is 3/15 and consequently the second one`s is 2/14 and taking them together, it is like 3/15*2/14=1/35
what do you say?

Thanks hoji!
Edited the reply.