As a result of a chemical spill, benzene is evaporating at a rate of $1$ gram

per minute into a room that is $6$ m$*6$ m$*3$ m in size and has a ventilation rate of $10$ m$3$

$/$ min.

a$.$ Compute the steady state concentration of benzene in the room

b$.$ Assuming the air in the room is initially free of benzene, compute the time necessary for

benzene to reach $95$ percent of the steady$-$state concentration