There is a 10% chance that it won't snow all winter long. There is a 20% chance that schools will not be closed all winter long. What is the greatest possible probability that it will snow and schools will be closed during the winter?
(A) 55%
(B) 60%
(C) 70%
(D) 72%
(E) 80%
OA: E
need an approach to solve this one...
Probability
This topic has expert replies
-
- Legendary Member
- Posts: 645
- Joined: Wed Sep 05, 2007 4:37 am
- Location: India
- Thanked: 34 times
- Followed by:5 members
800GMAT,
10% chance that it won't snow all winter long => 90% chance that it will snow all winter long
20% chance that schools will not be closed all winter long => 80% chance that schools will be closed all winter long
Combining these two statements together, we can get that there is 80% chance that schools will be closed all winter long and it will snow all winter long.
Am I clear 800GMAT?
10% chance that it won't snow all winter long => 90% chance that it will snow all winter long
20% chance that schools will not be closed all winter long => 80% chance that schools will be closed all winter long
Combining these two statements together, we can get that there is 80% chance that schools will be closed all winter long and it will snow all winter long.
Am I clear 800GMAT?
Correct me If I am wrong
Regards,
Amitava
Regards,
Amitava
-
- Master | Next Rank: 500 Posts
- Posts: 460
- Joined: Sun Mar 25, 2007 7:42 am
- Thanked: 27 times
This one seems to be a little weird to me
I agree that the max P that schools will be closed all winter long = 8/10 =80%
but if this is the P i.e the greatest possible probability that it will snow and schools will be closed during the winter.
then it means taking the P that it will snow = 1 i.e maximizing it
now if this corresponds to snow fall on atleast 1 day during winter (question mentions during winter & not all winter)
then the P =1 can be justified but in that case same will be applicable for the schools also so that too must considered as P of schools remaining closed on at least 1 day during winter, this P would be greater than 80%
so IMO the question has some logical flaw.
Any opinions/ corrections appreciated.
I agree that the max P that schools will be closed all winter long = 8/10 =80%
but if this is the P i.e the greatest possible probability that it will snow and schools will be closed during the winter.
then it means taking the P that it will snow = 1 i.e maximizing it
now if this corresponds to snow fall on atleast 1 day during winter (question mentions during winter & not all winter)
then the P =1 can be justified but in that case same will be applicable for the schools also so that too must considered as P of schools remaining closed on at least 1 day during winter, this P would be greater than 80%
so IMO the question has some logical flaw.
Any opinions/ corrections appreciated.
Regards
Samir
Samir
-
- Master | Next Rank: 500 Posts
- Posts: 460
- Joined: Sun Mar 25, 2007 7:42 am
- Thanked: 27 times
Hi Yuri,
I also meant that 72% is the answer which comes out, for E to be correct, the probability of snow should be 1 which produces a conflict here.
I also meant that 72% is the answer which comes out, for E to be correct, the probability of snow should be 1 which produces a conflict here.
Regards
Samir
Samir