Quantitative Comparison of Packet Switching and Circuit Switching

This question requires a little bit of background in probability $($but we'll try to help you though it in the solutions$).$ Consider the two scenarios below:

A circuit$-$switching scenario in which Ncs users, each requiring a bandwidth of $10$ Mbps$,$ must share a link of capacity $150$ Mbps$.$

A packet$-$switching scenario with Nps users sharing a $150$ Mbps link, where each user again requires $10$ Mbps when transmitting, but only needs to transmit $20$ percent of the time.