can someone help with letter D and E for both number one and two stop sending me links trying to hack me im not pressing on the link so stop wasting your time

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?