First find how long Carly runs the second week: 2 miles * 2 + 3 = <<2*2+3=7>>7 miles.
Then find how long she runs in the third week: 9/7 * 7 miles = <<9/7*7=9>>9 miles.
Then subtract the 5 miles reduction from when she was injured: 9 miles - 5 miles = <<9-5=4>>4 miles.
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