选择题
2016 AMC 8 Problem 4: Cheenu Per Mile
When Cheenu was a boy, he could run 15 miles in 3 hours and 30 minutes. As an old man, he can now walk 10 miles in 4 hours. How many minutes longer does it take for him to walk a mile now compared to when he was a boy?
2016 AMC 8 第4题：Cheenu 每英里
当奇努还是个小男孩的时候，他可以在 3 小时 30 分钟内跑完 15 英里。作为一名老人，他现在可以在 4 小时内步行 10 英里。与小时候相比，他现在步行一英里需要多花几分钟
A.
6
B.
10
C.
15
D.
18
E.
30