Can you break down the solution for me for this math problem: Carly is trying to get in shape to try out for the soccer team. She starts by running 2 miles a week. The second week, she runs twice as long plus 3 extra miles per week. The third week she runs 9/7 as much as she ran the second week. The week after that, she sprains her ankle and has to reduce her running time by 5 miles per week. How many miles did she run the week she was injured?