Chapter 1 - Equations and Inequalities - 1.2 Applications and Modeling with Linear Equations - 1.2 Exercises - Page 104: 44

(a) $V=900x\ ft^3/hr$ (b) $A=0.06x$ (c) $2.4$ (d) $3.3$

(a) For $x$ students, the total ventilation should be $V=15x\ (ft^3/min)(60min/hr)=900x\ ft^3/hr$ (b) To keep the room properly ventilated, we need $900x=15,000A$ which gives $A=0.06x$ (c) For $x=40$, we have $A=0.06(40)=2.4$ (d) The increase factor can be found as $\frac{50}{15}\approx3.3$