I made comparison with boat stream problem.Considered elevator as river,the man as a boat .
Distance:steps,Speed:steps per second,
60 steps in 60 sec=1 sps [StepPerSec]
80 steps in 50 sec=8/5 sps
Speed1 s1 would be (1sps +e) [Considered elevator speed as e sps,added since its downstream]
Speed2 s2 would be (8/5sps +e)
In the above distance is constant so s1*t1=s2*t2 so s1/s2=t2/t1.We solve this equation we get e=2 sps
Now total distance=elevator steps= s1 * t1 =(1 sps + 2sps) * 60 = 3*60 = 180.