Two tons of water is pumped into a tank 15 ft. high in 5 minutes. Determine the power output of the pump.

Assuming short tons,

... (2000 lb/ton) * (2 ton) * (15 ft) / (5 min) / (33000 ft·lb/min) / (1 hp)

... = (2000*2*15 / (5*33000) hp

... ≈ 0.364 hp

If you want something other than horsepower, you need to Google the desired conversion.