If ad/db = ae/ec, then line segment is parallel to line segment .choices for first ? : - ad- dechoices for second ? : - fg-bc

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?