Plz hurry 50 points!

solve n -> which number?

this is an inequality problem.

n - 4 -> 13

<-14-15-16-17-18-19-20-21-22-> ; # number line

9

11

17

18

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?