Probability Question

[wawan.widiyo]

Out of 100 lottery tickets, each having 50% chanse of winning, 2 tickets are bought at random. What is the probability that at least one ticket will win?

A. 1/4
B. 1/2
C. 49/198
D. 149/198
E. 3/4

Ans. D
(N,N) = 1/2 * 49/99 = 49/198

Probability of at least one ticket to win = 1 -(N,N) = 1 -49/198 =149/198

I still confuse with value 49/99 from answer key.

[RonPurewal]

Out of 100 lottery tickets, each having 50% chanse of winning, 2 tickets are bought at random. What is the probability that at least one ticket will win?

A. 1/4
B. 1/2
C. 49/198
D. 149/198
E. 3/4

Ans. D
(N,N) = 1/2 * 49/99 = 49/198

Probability of at least one ticket to win = 1 -(N,N) = 1 -49/198 =149/198

I still confuse with value 49/99 from answer key.

hi -

a couple of things:

* what are you actually asking us here? i don't actually see a question anywhere in this post.

* this problem is clearly not from the GMATPREP SOFTWARE, unless it has been heavily paraphrased.
could you please do one of the following things:
(a) type in the wording of the problem EXACTLY as stated in the gmatprep software (if the problem is from that software), or
(b) tell us the source of the problem (if the problem is not from that software, as i suspect)?

* also, you mentioned "confusion with the answer 49/99 from the answer key".
what exactly does this mean?
i don't really understand what this means, especially in light of the fact that 49/99 is not one of the three answer choices you've provided.

[wawan.widiyo]

Out of 100 lottery tickets, each having 50% chanse of winning, 2 tickets are bought at random. What is the probability that at least one ticket will win?

A. 1/4
B. 1/2
C. 49/198
D. 149/198
E. 3/4

Ans. D
(N,N) = 1/2 * 49/99 = 49/198

Probability of at least one ticket to win = 1 -(N,N) = 1 -49/198 =149/198

I still confuse with value 49/99 from answer key.

hi -

a couple of things:

* what are you actually asking us here? i don't actually see a question anywhere in this post.

* this problem is clearly not from the GMATPREP SOFTWARE, unless it has been heavily paraphrased.
could you please do one of the following things:
(a) type in the wording of the problem EXACTLY as stated in the gmatprep software (if the problem is from that software), or
(b) tell us the source of the problem (if the problem is not from that software, as i suspect)?

* also, you mentioned "confusion with the answer 49/99 from the answer key".
what exactly does this mean?
i don't really understand what this means, especially in light of the fact that 49/99 is not one of the three answer choices you've provided.

Ron,

sorry, i have mistaken put my question here. It should be put at GMAT other question insted of GMAT from mba.com (prep. software) isn'it?
The source of this question is from GMAT forum as well.

[RonPurewal]

Ron,

sorry, i have mistaken put my question here. It should be put at GMAT other question insted of GMAT from mba.com (prep. software) isn'it?
The source of this question is from GMAT forum as well.

what is "GMAT other question"? that is not specific enough; we need to know the EXACT SOURCE from which the question comes.

we need SPECIFIC sources for non-official questions, since some sources are banned and others are allowed.
if you don't know the SPECIFIC source of the problem, then you can't post it here.
if you do, then please post that source.