Problem: A 3.20-kN piano is lifted by three workers at a constant speed to an apartment 21.8 m above the street using a pulley system fastened to the roof of the building. Each worker is able to deliver 165 W of power, and the pulley system is 75.0% efficient (so that 25.0% of the mechanical energy is lost due to friction in the pulley). Neglecting the mass of the pulley,

Part A: Find the time required to lift the piano from the street to the apartment.

I need help to determine the time required to lift the piano from the street to the apartment.