Two trucks leave a factory at the same time one truck travels east at 60 miles per hour and the other travels west at 30 miles per hour. In how many hours will they be 150 miles apart

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?