SOLUTION: 7. A flashlight has 6 batteries, 2 of which are defective. If 2 are selected at random without replacement, find the probability that both are defective.

Algebra ->  Probability-and-statistics -> SOLUTION: 7. A flashlight has 6 batteries, 2 of which are defective. If 2 are selected at random without replacement, find the probability that both are defective.      Log On


   

Question 268772: 7. A flashlight has 6 batteries, 2 of which are defective. If 2 are selected at random without replacement, find the probability that both are defective.
Found 2 solutions by palanisamy, stanbon:
Answer by palanisamy(496) About Me  (Show Source):
You can put this solution on YOUR website!
Out of 6 batteries 2 can be selected in 6C2 = (6*5)/1*2 = 15 ways.
Two batteries are defective.
Out of 2 defective batteries 2 can be selected in 2C2 = 1 way.
Probability of selecting both batteries defective = 1/15

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A flashlight has 6 batteries, 2 of which are defective. If 2 are selected at random without replacement, find the probability that both are defective.
---------------------
# of pairs of defectives: 2C2 = 1
-------------------
# of random pairs: 6C2 = 15
---------------------------------------
P(select 2 defective) = 1/15
==================================
Cheers,
Stan H.