An elevator weighing 15000 newtons s raised in 50 seconds. If the distance between stories is 3.0 meters how much power is required of the motor?

You didn't say so, but I assume we're talking about the elevator rising by 1 story.

The work it has to do is (force) x (distance) = (15,000 N) x (3 m) = 45,000 Joules.

Power = (work) / (time).

Power = (45,000 Joules) / (50 seconds)

Power = 900 joules/sec

Power = 900 watts

Power = about 1.206 Horsepower