Let t be time in seconds and let r(t) be the rate, in gallons per second, that water enters a reservoir:

r(t)=700−40t.

a) For 0≤t≤30, when does the reservoir have the most water?
b) For 0≤t≤30, when does the reservoir have the least water

1 answer

Use: r(t) = 700-40t

Determine whether the rate is ever zero within the domain, and if it is positive or negative prior and after that point. That is, are there local minima or maxima within the domain 0≤t≤30?

Use integration to determine the volume of the reservoir V(t) with respect to the initial volume V(0).

Find: V(t) = V(0) + ∫{0↔t} (700-40x) dx

Evaluate V(t) of the points of interest. At t=0, t=30, and of local minima or maxima you found within the domain.

The answers are the t of least and greatest V(t).