Raul is building a house. on day 1, he uses 3 bags of cement. on each of the following 3 days, he uses 3 times the number of bags used the previous day. how many bags of cement does he use in the last 3 days?

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?