Joe works two part time jobs. One week Joe worked 8 hours at one job, earning $150, and 4.5 hours at other job, earning $90. What were his average hourly earnings for the week ？（）

A.$8.00

B.$9.60

C.$16.00

D.$19.20

E.$32.00

男性，44岁，反复心悸、胸闷2小时入院。既往心电图示P-R间期短于0.12秒，QRS波群起始部分粗钝（称delta波），终末部分正常。入院心率280/分钟。心电图示P波消失，出现f波，R-R间期绝对不等。

患者目前首选的处理是（）

A.静脉推注胺碘酮

B.静脉推注普罗帕酮

C.静脉推注毛花苷C

D.电复律

E.心脏起搏