Kaunteya wrote:On Saturday morning, Bill will begin a camping vacation and he will return home at the end of the first day on which it rains. If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Bill will return home at the end of the day on the following Monday?
A. 0.008
B. 0.128
C. 0.488
D. 0.512
E. 0.640

Again another one for you guys to tackle.

The question is asking us "what's the probability that Monday is the first day on which it rains?"

So, we want:

no rain on Saturday, no rain on Sunday, rain on Monday.

so: (.8)(.8)(.2) = (.64)(.2) = .128

Thanks Stuart

Thanks Stuart, that is what I got, but there was no answer to the question. I think I am finally sort of getting the hang of probability, permutations and combination. Could you do me a favour? Could you please post up a few permutation, combination and probability questions that you find that the REAL GMAT may test. That way I can decide if my knowledge on this material is strong enough. Thanks mate.

Kaunteya