You may calculate the productivity based on each factor of production, including shoemakers, sewing machines and stamping machines. The productivity=output/number of factor of production.So, productivity of labor=2600/50=52, of sewing machine=185.7 and of stamping machine=371.4.
Or you can group them into labor, 50, and capital, 14+7=21. So
the productivity of labor=2600/50=52, of capital=123.8