$3.($ Points : $10)$ Solve the following problem : Consider the following network configuration $.$ Router RouterRouter Router $10$ Mbps $10$ Mbps Source $10$ Mbps $10$ Mbps $10$ Mbps Destination Source wants to transmit $4$ packets to the destination $.$ Each packet is $1$ Mb long. How long will the $4$ packets take to reach at the destination $?$ Capacity of each communication link is $10$ Mbps $($as shown in the figure$).$ Neglect propagation delay, processing delay $,$ and queuing delay.$)$