I need the step by step to solve this problem

It takes one minute for an elevator to climb 20 floors. Each floor is 3 meters high. What is the average speed of the lift in meters per second?

20 floors in one minute equal to 60 seconds,

1 floor is 3 meters 20 floors equal 60 meters

So 60 seconds you go 60 meters or 1 meter per second.

I so hope this is right but I am sure it is not worked the way you are required to solve the problem.

You can if you explain it properly, and your answer seems fine to me. You can also put it that way:

Speed = Distance/Time

Total distance = 20 x 3 = 60 m

Speed = 60 m/ 1 min = 60m/min

Convert into m/s = 60 m/ 60 s = 1 m/s