Answer:
1 hours = 60 min
60 x 9/10 = 54 min
3 divided by 54 = 1/18
so she walks 1/18 miles per hour.
Im not sure though. It might be 3 divided by 9/10 = 3 1/3. I’m not that confident in my answer. But it is definitely one of them, either 1/18 or 3 1/3.