A missile has a guidance device which $issensitiveto$ both temperature, $tC,$

and humidity, $h.$ The range $inkm$ over which the missile can $be$ controlled $is$

given $by$

Range $=28,600-5t^2-6ht-3h^2+400t+300h.$

What are the optimal atmospheric conditions for controlling the missile?

$h=$

$i$

$\%$

$t=$

${?}_{i}C$