We really need the picture in order to answer.
-- We suspect that the tank may be a cylinder, and that 'r' and 'h'
may be its radius and height respectively. But we can't be sure.
-- Even if we were sure of the tank's shape, we don't know whether
the tank is a laying down cylinder or a standing up cylinder.
-- Most perplexing of all, we have no idea where on the tank
the spout is located. That makes a big difference.
