$1.$ A toll$-$free freeway has been constructed between the two cities. The total cost to travel between the two cities is expressed as C $=45+0\mathrm{.}6$V$,$ where C is the cost$/$veh in $$ and V is the trafficvolume in veh$/$h$.$ The demand for travel along the freeway is V $=3500-12$C$.$ a$)$ Determine thevolume of traffic along the freeway. b$)$ If a toll of $50$ is added, what will the volume along the freeway be$?$ And how much revenue will be generated?