Question 26
This vase is in the shape of a prism. The front and back faces are not rectangles, but the other four faces are. The front face has top and bottom sides parallel, and its left and right sides are of equal length. When I fill the vase to $\frac13$ of its height, the vase is $\frac12$ full. When I fill the vase to $\frac12$ of its height, the vase is $\frac mn$ full. Here $m,n$ are positive integers with no common factor other than 1. What is $m+n$?
