A message is broken up into 15 independent packets in order to transmit them through a network. Routers are 100 km apart and the packets propagate at...

A message is broken up into 15 independent packets in order to transmit them through a network. Routers are 100 km apart and the packets propagate at a speed of 200 KM/Hr. 

The routers are implementing the FIFO protocol and each packet experiences a delay of 10 seconds at Router 1; 20 seconds at Router 2 and 5 seconds at Router 3.

Suppose that the entire message travels 300 KM, beginning at the input side of Router 1, passing through Router 2 and ending 100 KM after Router 3.

What is the end to end delay of this network?