Related Rates/Tank problem

[tcg93]

Why is the answer C?

[Stormer]

dv/dt=2-kRootH
V=nr^2h

nr^2=2
V=2h

dv/dh = 2
dh/dv=1/2

dh/dt = dv/dt x dh/dv

=1/2 x 2-kRootH

[tcg93]

dv/dt=2-kRootH
V=nr^2h

nr^2=2
V=2h

dv/dh = 2
dh/dv=1/2

dh/dt = dv/dt x dh/dv

=1/2 x 2-kRootH

Why is dv/dt=2-kRootH ??

Isn't it only fresh water being poured in so you're meant to exclude that?

[mark_alec]

Isn't it only fresh water being poured in so you're meant to exclude that?

The salt is irrelevant for this question, as they just want to know the change in height with respect to time.

If they asked you to model the mass of salt as a function of time, it would be different.

[Martoman]

yeah exactly my thoughts. Its a trick.