please explain in detail
Probem 4 (10) The disc containing the only copy of your homework just got corrupted, and the disk got mixed up with two other corrupted discs that were lying around. It is equally likely that any of the three discs holds the corrupted remains of your homework. Your computer expert friend offers to have a look, and you know from past experience that his probability of finding your homework from any disc is 0.35 (assuming the homework is there). Given that he searches on disc 1 but cannot find your homework, what is the probability that your homework is on disc $i$, for $i=1,2,3$ ?