Easy math, but I'm dumb

V = (Vt/60)*t

Where Vt is the total volume.
The drain/filling rates are not dependant on the volume. They are constants.

I did not know that the question was asking for 1/60th of the total volume (of the container) and not just its volume (the volume of the liquid that is already in the container). I assumed the latter because the former was probably not worth making a thread for.