Can somebody explain common stock to me?

This year, druehl, inc., will produce 60 comma 000 hot water heaters at its plant in delaware, in order to meet expected global demand. to accomplish this, each laborer at the plant will work 200 hours per month. if the labor productivity at the plant is 0.25 hot water heaters per labor hour, how many laborers are employed at the plant? number of laborers employed by the plant = nothing laborers (round your answer to the nearest whole number).