In the modern tim e,cell phone reduces the cost of important inform a-tion,p lays a cruc ial role in both fac ilitate international and dom estic trades,as well as impacts the effic iency ofm ed ical service.Consider a c ity and estim ate from ava ilab le data the numberH of house-holds,w ith m m embers each,that in the past were serviced by land lines.Now,suppose that som e land lines are rep laced by cell phones.W e model theconsequences of th is change for electric ity utilization in the c ity,during the...
