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#1 2007-12-06 23:21:28
- gyanshrestha
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- Registered: 2007-11-06
- Posts: 41
probality
the probality of sovling a math problem by A is 0.25 and that of B is 0.35.
what is th probality that they solve the same problem when they try to solve together?
I know how to do it. But i really dot not uderstand why i am doing so. can anyone help me please?
i did it like that
p(not solving by A)=0.75
p(not solving by B) = 0.65
P( not solving by both)= 0.4875
P(solving by both) = 0.5125
why do we first find the 3rd line?
what is wrong with by finding multiplying 0.25 and 0.35?
Last edited by gyanshrestha (2007-12-07 17:16:46)
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#2 2007-12-06 23:38:40
- Identity
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- Registered: 2007-04-18
- Posts: 934
Re: probality
Sorry, the question isn't very clear, is this what you mean?
There are two ways of solving one problem. The probability that method A will succeed is given, as well as the probability that method B will succeed.
What is the probability of solving using both methods?
In this case there is not enough information! Does one method depend on the other?
Last edited by Identity (2007-12-06 23:41:02)
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#3 2007-12-07 17:15:42
- gyanshrestha
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- Registered: 2007-11-06
- Posts: 41
Re: probality
oh sorry
i mean what is the probality of getting solved the same question when the problems is given to both at the same time.
i have edited the question above.
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#4 2007-12-07 17:34:18
- John E. Franklin
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- Registered: 2005-08-29
- Posts: 3,588
Re: probality
If you multiply them together, the .25 and the .35, then
you get the intersection of the occurrences.
So you would get the chance that both of them solve it, both, meaning all 2 of them both get it.
Learn Venn Diagrams and karnuagh maps??
And then multiplying, is like ANDing, or the Intersection.
Make two circles or rectangles that intersect.
Inside one rectangle, guy#1 solves it.
Inside 2nd rectangle, guy#2 solves it.
Outside both rectangles, guy#2 and guy#1 both don't solve.
If one solves and the other doesn't, then the intersecting
part is getting True and False from the two rectangles.
XORing these gets a True. Anding is false, Oring is True.
I'm rambling...
igloo myrtilles fourmis
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