Bad Quality Problems
Bob Yang, depending on his mood, makes bad problems, troll problems, and good problems. He has a 5/7 chance of making a bad problem, and a 1/5 chance of making a troll problem. What is his chance of making a good problem? The answer is some fraction x/y; find 10y+x.
Note: The answer is not 0, but in real life, it might be. ;)