5(0) Anivals at a telephone book are considered to be folloning Poisson law of distributiou with an average sirme of 10 minutes between one arival and the next. Length of a phone call is assumed to be distributed exponentially with mean 3 minutes. (i) What is the probability that a person aniving at the booth win have to wait? (ii) What is the average leugth of queue that forms from tirne to time? (iii) The telephone de-rinent will install a second booth when convinced that an arival would expect to wait at least three minutes for the phone. By how much must the flow of anivals be increased in order to justify a second both