Abag contains 4 yellow marbles 6 red marbles 5 blue marbles 6 white marbles and 4 black marbles what is the theoretical probability of pulling a white marble from the bag

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?