A crime has occured in Carborough, involving a taxi. The police interviewed an eyewitness, who stated that the taxi involved was blue.

The police know that 85% of taxis in Carborough are blue, the other 15% being green. They also know that statistically witnesses in these situations tend to be correct 80% of the time - which means they report things wrong the other 20% of the time.

What is the probability that the taxi involved in the crime was actually blue?

Tom, I don't think your logic is correct here... How can the police be 96% sure the taxi is not green, but only 64% sure that it's blue? Since there are only blue and green taxis, any taxi that is not green must be blue, so the two percentages should be equal.

Posted by levik on 2002-05-24 06:50:56