Sally and Ben went outside the school to draw some very large shapes on the tarmac. None of the shapes they drew shared any sides with any other shape - they were all drawn separately although some small shapes were inside larger shapes. The children each had a box of ten sticks of chalk. Each stick drew $10$ metres before it was quite worn away. They both drew shapes with all sides one metre long.
Ben drew triangles, hexagons and squares. He drew $20$ shapes and still had two sticks of chalk left. How many of each shape did he draw?