问题
单项选择题
A group of 7 fishermen chartered a boat for a day to fish for flounder. The boat costs x dollars per day to rent. If the group can find 3 more fishermen on the docks who are willing to come aboard and share the rental costs, how much less will the rental cost be per person in terms of x ？（）
A. x/70
B. x/35
C. 3x/70
D. 3x/10
E. 3x/7
答案
参考答案：C
解析：
The difference in cost is the difference between x/7 and x/10. x/7-x/10=(10x-7x)/70 =3x/70.