求一道中位数题

yamajiao

GWD 9-Q14:




Yesterday each of the 35 members of a certain task force spent some time working on project P.The graph shows the number of hours and the number of members who spent that number of hours working on project P yesterday.What was the median number of hours that the members of the task force spent working on project P yesterday?


A.2
B.3
C.4
D.5
E.6

首先，我不知道这道中位数题怎么解答，
其次，这套涛涛GWD和TT讨论帖对不上号，为什么？
求解！！

遭了，图片怎么插啊？