a chain weighing 5 ft/lb hangs vertically from a winch located 12 ft above the ground and the free end of the chain is just touching the ground. Find the work by the winch in pulling the whole chain

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?