2014 AMC 8 Problem 17

George walks 1 mile to school. He leaves home at the same time each day, walks at a steady speed of 3 miles per hour, and arrives just as school begins. Today he was distracted by the pleasant weather and walked the first \frac{1}{2} mile at a speed of only 2 miles per hour. At how many miles per hour must George run the last \frac{1}{2} mile in order to arrive just as school begins today?

\textbf{(A) }4\qquad\textbf{(B) }6\qquad\textbf{(C) }8\qquad\textbf{(D) }10\qquad\textbf{(E) }12

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.