99.9% because the fortune teller charged 24.99 an hour.
A man must go through a type of surgery that has a 99.9% success rate. A future teller who can predict future events with 99% accuracy tells the man that his surgery will be unsuccessful. What is the probability that the surgery will be successful?
This is the old "irresistable force vs the immovable object" discussion.
Q. Are there any surgeries or, more significantly, "future tellers" with that proven success rate?
One wonders why someone undergoing such an obviously routine procedure would seek a clairvoyant second opinion. : /
Whether or not one values the medical opinion over the superstitious one (that .1% is daunting), the general odds of success remain unchanged. If one finds the latter opinion more compelling, perhaps the surgery should be cancelled in favor of seeking a voodoo shaman. There's some good odds for you.
The odds of failure on the surgery does not change.
If the fortune teller is correct, it just means the patient was the 1 in 1000 that had an unsuccessful outcome.
Hint---are these "independent" events in terms of probability?