This is a triangularprism. Its faces are triangular, but the <em>lateral</em><em> </em>faces are rectangular. All prisms will have lateral faces shaped as rectangles. Do not <em>ever</em> forget this.
So all you do is you divide 2 1/2 by .25 and you get 10 then you know one fourth or 25% of that package is 10 berries so the rest or 30% left over is 30 berries.
