A) write an equation that models the total ventilation V(in cubic feet per hour) necessary for a classroom with x students.

B) A common unit of ventilation is an air change per hour(ach). 1 ach is equivalent to exchanging all of the air in a room every hour. If x students are in a classroom having volume 15,000ft^3, determine how many air exchanges per hour (A) are necessary to keep the room properly ventilated.

C) Find the nessary number of ach A if the classroom has 40 students in it.

D) In areas like bars and lounges that allow smoking, the ventilation rate should be increased to 50ft^3 per min per person. Compared to classrooms, ventilation should be increased by what factor in heavy smoking areas?