The sum of 3 times a number and 4 is between -8 and 10. define a variable, write an inequality, and solve the problem.

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?