I tried solving this but failed many times. I couldn't really wrap my head around the right point to start. Here's the question:
Students A, B, and C each independently answer a question on a test. The probability of getting the correct answer is 0.9 for A, 0.7 for B, and 0.4 for C. If 2 of them get the correct answer, what is the probability C was the one with the wrong answer?
Even hints would suffice. Not really necessarily looking for the answer but just the correct headstart. Thanks.