MAT190: Chapter 3 - Related Rates (Inverted Pyramid)

[johnnolen]

Way too much work. The flux of a vector field is the surface integral of said vector field over the surface normal to the vector field: Q = A·v.

In this case, Q = dV/dt, A = b^2, and v = dh/dt. Substituting the given values: 35 = (3/4)^2 · dh/dt.
Therefore, dh/dt = 35 · 16/9 = 560/9.
dh/dt = 62.222 ... ◼