Since ID field in an IP packet is 16 bits long, you can have 216 unique packet IDs. Therefore we can send 216 =65535 packets without cycling through the IP datagram IDs.
We need to transmit these 65535 packets in 15 seconds, so # of packets that need to be transmitted per second= 65535/15=4369
Packet size=16 Kilo bits(Kb)
Max line speed of router( in Mega Bytes per second)= (4369*16)/1000*8 =8.738 MBps