$10\mathrm{.}9$ Determine the required tower volume for Ex$.10\mathrm{.}3$ if water leaves the tower at

$($a$)90F$ and

$($b$)80F.$

You$-$may use the ppproximate$-$methe Eqs.$(10\mathrm{.}27)(10\mathrm{.}29).$ Use the NTU method.

rigure

w$.$is senematic cooming tower for Prob. $10\mathrm{.}8.$