2.5, 2.6, and 2.7 please

2.5 2.6 What is the average call holding time in seconds of a group of circuits that has accumulated 0.4445 Erlang of usage in an hour, based on 330 call artempts with 10 calls overflowing (i.c., calls not served)? A trunk accumulated 0.75 Erlang of usage while 9 calls were carried in an hour with no overflow. What is the average holding time per call in seconds? A switching system is designed to support 80,000 subscribers during the BHL Each subscriber generates an average of 1.8 calls/hour during the BH with an average call holding time of 100 seconds. Calculate the offered traffic load to the switching system