$12-7.$ Would the fan shown in Fig. $12-9$ be suitable for use in a system requiring $($a$)30,000cfm$ at $5\mathrm{.}0in.wg$ total pressure? $($b$)5000$ cfm at $1\mathrm{.}5in.wg$ total pressure? $($c$)15,000cfm$ at $4\mathrm{.}0$ in$.$ wg total pressure? Explain.

Outlet velocity, fpm

Figure $12-9$ Performance chart showing combination of fan and system. $($Reprinted by permission from ASHRAE Journal, Vol. $14,$ Part I, No$.1,1972.)$