Suppose users share a 1, 280 kbps link. Also suppose each user requires 64 kbps when transmitting, but each user transmits only 10% of the time. (See the discussion of statistical multiplexing in Section 1.3.) When circuit switching is used, how many users can be supported? For the remainder of this problem, suppose packet switching is used. Find the probability that a given user is transmitting. Suppose there are 50 users. Find the probability that at any given time, exactly n users are transmitting simultaneously. Find the probability that there are more than 20 users transmitting simultaneously. (You need to calculate the exact value, not just the formula.)