1. R, S, and T are collinear. S is between R and T. RS = 2w + 1, ST = w -1, and RT = 18. Use the information given to determine the length of RS

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?