Cooper Section $8\mathrm{.}13$ #$15$

$On$ a certain island there are two populations $of$ deer. After $t$ years, the numbers $of$ deer $in$ the two populations are $p(t)=200e^t$ and $q(t)=2000e^{-t}.$ When $is$ the total population

smallest?

The total population $is$ smallest when $t=$