选择题
2014 AMC 8 Problem 17: Running to School
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 walked the first 1/2 mile at only 2 miles per hour. At how many miles per hour must George run the last 1/2 mile in order to arrive just as school begins today?
2014 AMC 8 第17题 ：跑步上学
George步行1英里到学校。他每天在同一时间离开家，以每小时3英里的稳定速度行走，并在学校开始时到达。今天，他以每小时2英里的速度走了前半英里。乔治必须以每小时多少英里的速度跑完最后1/2英里，才能在今天开学时到达？
A.
4
B.
6
C.
8
D.
10
E.
12