Equation end-to-end delay = N * (L / R) simplifies the delay of sending one packet of length L over N links of transmission rate R.

Suppose you have the following network and that that the equation end-to-end delay = N * (L / R) is true. In the following schematic of a network, each letter is a router.

A ------------- B --------------- C -------------- D

1) If you have @ packets of size L that are loaded from A and travel to D. Transmission rate is R for all the links. All packets are loaded on node/router A at the same time. At what time will the last packet will arrive at router D? Express your answer in terms of L and R.

2) In addition to the packets loaded on router A, suppose that an additional packet is loaded on router C at time 0 traveling to D. At what time will the last packet arrive at router D?

3) In addition to the packets loaded in on router A, suppose that another packet arrives on router C at time 5 * L / R traveling to D. At what time will the last packet arrive at router D?