有道听力题,不晓得怎么算哪~那个来教教我哇

题目

有道听力题,不晓得怎么算哪~那个来教教我哇
听力原文:
M:Did you call your parents?
W:Yes.It cost me one yuan.
M:Oh,it's very cheap.
W:Yes.I spent 40 fen on the first three minutes,then 10 fen more on each minute.
How long did the woman call her parents?
A:8 minutes.
B:6 minutes.
C:9 minutes.
C

答案

一共花费1元 1元=100分 前三分钟40分 剩下的60分 每分钟10分 60/10=6分钟 3+6=9分钟