I was wondering if someone could help me with this...

A test for the presence of E. coli in water detects the bacteria 97% of the time when the bacteria is present, but also gives a false positive test 2% of the time, wrongly indicating the presence of E. coli in uninfected water.

If 10% of the water samples tested contain E. coli, what is the probability that a test result indicating the presence of the bacteria is accurate?

Thanks for any help!