问题
单项选择题
Last year the annual premium on a certain hospitalization insurance policy was $408, and the policy paid 80 percent of any hospital expenses incurred. If the amount paid by the insurance policy last year was equal to the annual premium plus the amount of hospital expenses not paid by the policy, what was the total amount of hospital expenses last year ？（）
A．$850.00
B．$680.00
C．$640.00
D．$510.00
E．$326.40
答案
参考答案：B
解析：
做对此题的关键是读懂题目，设去年的医疗费用为x美元，则根据题意可得：
408+x×20%=x·80%
→x=680美元