determination of probability Recently I have faced a problem related to probability.I have tried it by bayseian theorem but failed.Here is the problem:
A doctor knows that pneumonia causes a fever 95% of the time. She knows that if a person is selected 
randomly from the pneumonia. 1 in 100 people suffer from fever. You can go to the doctor complaining 
about the symptom of having a fever (evidence).  What is the probability that pneumonia is the cause of 
this symptom?
Can anyone give some hints or how can i solve it?
 A: There are many ambiguities in the question itself and the question can be interpreted in two ways. 


*

*At first it says that "pneumonia causes a fever 95% of the time" and later it is being contradictory/(false in terms of stats) by saying " if a person is selected randomly from the pneumonia. 1 in 100 people suffer from fever." So, how come only 1 in 100 person are suffering from fever when pneumonia itself causes fever 95% of the time. If we go by this, then it should have been "...95 in 100 people suffer from fever".


Another way to interpret the question is,


*Since there a 'fullstop' between "if a person..." and "1 in 100...". Therefore it in this way, the line "She knows that if a person is selected randomly from the pneumonia" will make no sense at all.


Putting everything in one and somehow trying to get the answer, may return multiple different answers because different people will interpret this question as differently.
But the answer would be:
Consider that there are only 100 people in that town. Out of which it is given that 1 person suffers from "fever". We are also provided that pneumonia causes fever 95% of the times. Therefore, for that "1" person, who suffers from fever, there would be $ 95/100 * 100 = 95\% $ person chances that it is caused by pneumonia. 
