Hello,
Can you please tell me how to solve this:
What is the probability that it will rain tomorrow?
1.The probability that it rains today is 40%.
2.If it rains today, the probability that it will rain tomorrow will increase by 10%.
OA: E
1) In-suff.
2) In-suff.
I was wondering how to solve for E ?
Thanks for your help.
Regards,
Sri
What is the probability that it will rain tomorrow?
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Hello Sri,
According to me it is a natural phenomena and other factors like wind direction & humidity also should be considered which are missing in both the statements. So, both are in-sufficient in this case.
Probability can only be determined in terms of symmetrical outcomes (getting head in a coin toss) or relative frequencies (million tosses for eg).
Regards,
Tushar
According to me it is a natural phenomena and other factors like wind direction & humidity also should be considered which are missing in both the statements. So, both are in-sufficient in this case.
Probability can only be determined in terms of symmetrical outcomes (getting head in a coin toss) or relative frequencies (million tosses for eg).
Regards,
Tushar
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To find: Probability for Rain tomorrow
Statement 1:
Today's Probability = 40%
No info for tomorrow
INSUFFICIENT
Statement 2:
Tomorrow's probability = Todays + 10%
INSUFFICIENT
Combining...
it rains today = 40%
Tomorrow's probability = Todays + 10%
if it rains today, then probability for tomo = 40 + 10 = 50%
if it doesn't rains today, then probability for tomo = 40%
So, we are not sure
INSUFFICIENT
[spoiler]{E}[/spoiler]
Statement 1:
Today's Probability = 40%
No info for tomorrow
INSUFFICIENT
Statement 2:
Tomorrow's probability = Todays + 10%
INSUFFICIENT
Combining...
it rains today = 40%
Tomorrow's probability = Todays + 10%
if it rains today, then probability for tomo = 40 + 10 = 50%
if it doesn't rains today, then probability for tomo = 40%
So, we are not sure
INSUFFICIENT
[spoiler]{E}[/spoiler]
Last edited by theCodeToGMAT on Wed May 07, 2014 6:52 pm, edited 1 time in total.
R A H U L
Rahul,
In the last para you mentioned; if it rains today, then probability for tomorrow = 40 - 10 = 30%
Don't you think it should be 40 + 10 = 50% (as statement2 in question says increase of 10% if it rains today)
Regards,
Tushar
In the last para you mentioned; if it rains today, then probability for tomorrow = 40 - 10 = 30%
Don't you think it should be 40 + 10 = 50% (as statement2 in question says increase of 10% if it rains today)
Regards,
Tushar
- theCodeToGMAT
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Yep, I made a typo!Tushar14 wrote:Rahul,
In the last para you mentioned; if it rains today, then probability for tomorrow = 40 - 10 = 30%
Don't you think it should be 40 + 10 = 50% (as statement2 in question says increase of 10% if it rains today)
Regards,
Tushar
Thanks!
R A H U L
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Guys, there is a much simpler explanation:
NOBODY SAID THAT THE PROBABILITY OF RAIN TOMORROW STARTS AT 40%!
For all we know the baseline probability of rain tomorrow is 0%, so that if it rains today the probability tomorrow will be exactly 10%. Tomorrow could also have a baseline probability of rain of 90%, so that if it rains today the probability of rain tomorrow is 100% ... and really we could have any other probability in between.
Be careful here!
NOBODY SAID THAT THE PROBABILITY OF RAIN TOMORROW STARTS AT 40%!
For all we know the baseline probability of rain tomorrow is 0%, so that if it rains today the probability tomorrow will be exactly 10%. Tomorrow could also have a baseline probability of rain of 90%, so that if it rains today the probability of rain tomorrow is 100% ... and really we could have any other probability in between.
Be careful here!