You can factor like terms out of both the top and bottom, and then cancel them out. If you look at 50 and 75, you might notice that they both share a common factor of 5. When you factor 5 out of 50 and 75, you have the fraction

This is not the entire solution. While the 5'vs cancel, you can still factor a few more fives out of 10/15. This leaves you with the fraction

Which is the solution.