A candidate is selected for interview of management trainees for 3 companies. For the first company, there are 12 candidates, for the second there are 15 candidates and for the third, there are 10 candidates. Find the probability that he is selected in at least one of the companies. Assume that 1 candidate will be selected in each of the interviews, and all candidates appearing for the interview have an equal probability of getting selected.

Fill in the answer in the text box, in the form of an irreducible fraction A/B where A and B are two integers.

e.g. Your answer should resemble something like:

3/4  

(This is NOT the answer, just a demonstration of what the answering format should resemble).