Fragment Offset value is calculated as a multiple of eight bytes so,FO for 2nd fragment will be 185 ( i.e.185x8 = 1480) which means that the data portion of 2nd fragment starts 1480 bytes into the original IP datagram
Suppose an IP datagram is divided into 2 fragments, all fragments will have SAME identifier value.So, as per your scenario :
1st Fragment : ID = 1, DF=0, MF=1, FO = 0
2nd Fragment: ID = 1, DF=0, MF=0 , FO= 185
The length of 1st fragment is 1500(Including 20 bytes for IP header) resulting in datagram size of 1480 thus FO = 185 for 2nd fragment.
If you need detailed insight, refer to following link esp. study this visual diagram for better understanding
Hope this helps.