$\text { A calf that weighs } 70 \text { pounds at birth gains weight at the rate } \frac { d w } { d t } = k ( 1200 - w ) \text {, }$

Multiple Choice

$\text { A calf that weighs } 70 \text { pounds at birth gains weight at the rate } \frac { d w } { d t } = k ( 1200 - w ) \text {, }$ where $w$ is weight in pounds and $t$ is time in years. Use a computer algebra system to solve the differential equation for $k = 0.9$ .

A) $w = 70 e ^ { - 0.9 t }$
B) $w = 1130 e ^ { - 0.9 t }$
C) $w = 1200 - 1130 e ^ { - 0.9 t }$
D) $w = 1130 - 0.9 e ^ { - t }$
E) $w = 1200 e ^ { t } - 1130 e ^ { - 0.9 t }$