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A square park has a running track around it where people come to get exercise most days of fair weather. On the north side there is a water fountain alongside the track located x feet west of the northeast corner of the park. Jill and Nancy are running counterclockwise around the track together, when Nancy stops to get a drink at the fountain but Jill keeps running along the track. The track measures 3x feet from the fountain to the northwest corner, where Jill turns left and heads south on the track. Nancy decides to cut across the park and runs diagonally toward the southwest corner where she meets Jill, and they continue running together, east along the south side of the park. The two girls run at the same rate in all these situations. How far, in terms of x, was Jill east from the northwest corner when Nancy finished her drink and began to cut across the park to meet her?
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