Juan got on an elevator at the middle floor of a building, went up 4 floors, down 3 floors, up one floor, down 9 floors, where he left the elevator on the ground floor.
a. how many floors are in the building?
b. explain

There are 14 floors in the building, because since Juan went up 4 floors, down 3 floors, and up one floor; so we know that he is 2 floors above from where he originally started. Once he went down 9 floors he passed the starting point and went to the bottom of the building. So, the middle must have been the 7th floor. Once I knew that I multiplied 7*2 and it got me 14. So in total there are 14 floors. I hope this helped ^^