Problem #$3(7\mathrm{.}3$W$)[10$ pts$]$

A freeway has a capacity of $7500ve\frac{h}{h}$ in one direction that has three lanes. In one morning,

traffic arrived at $3300ve\frac{h}{h}.$ At $15$ minutes, a crash occurred and blocked all the lanes. At $60$

minutes, police opened two lanes. The capacity of two lanes, $,$ was unknown but the queue

disappeared at $120$ minutes. Draw the cumulative arrival and cumulative discharge curves versus

time and determine, and the maximum queue length. Hint: convert all the volume and capacity

to the unit of vehicles per minute when drawing the curves.