In order to solve this problem you have to add the distance Harriet traveled away from her starting point which is 2 1/4+3/4. Then you should end up with 3 miles. After that it says she went back on the same route so you have to double the distance. So in total she rode 6 miles.
5 is the answer. 100% of any number is that number
All work is shown in picture below.