A closed ecosystem contains two species

MATHEMATICS · Subjective · AP · Calculus AB · Contextual Applications of Differentiation · Contextual Applications of Differentiation

Problem

A closed ecosystem contains two species,

A

and

B

, whose populations obey

A(t)+B(t)=1200

for all

t

. At a certain moment,

A

is increasing at

15

individuals per day. Determine

\displaystyle \frac{dB}{dt}

(units: individuals per day) at that moment.