0
(days)
10
22
30
W'(t)
0.6
0.7
1.0
0.5
(GL per day)
The twice-differentiable function $W'$ models the volume of water in a reservoir at time $t$, where $W(t)$ is measured in (GL)
and $t$ is measured in days. The table above gives values of $W'(t)$ sampled at various times during the time interval $0 \le t \le$
30 days. At time $t = 30$, the reservoir contains 125 gigaliters of water.
3.
The equation $A = 0.3W^{2/3}$ gives the relationship between the area $A$, in square kilometers, of the surface of the
reservoir, and the volume of the water $W(t)$, in gigaliters, in the reservoir. Find the instantaneous rate of change of
A, in square kilometer per day, with respect to $t$ when $t = 30$ days.
