1. **State the problem:** Evelyn rode two trains, first for 137.13 miles and then for 51.1 miles. We need to find the total distance she rode. 2. **Formula used:** To find the total distance, we add the distances traveled on each train. $$\text{Total distance} = \text{Distance on first train} + \text{Distance on second train}$$ 3. **Calculate:** $$137.13 + 51.1 = 188.23$$ 4. **Explanation:** Adding the two distances gives the total miles Evelyn rode. **Final answer:** Evelyn rode a total of $188.23$ miles.