Brett took elevator a from the 6th floor to the lobby, the 0 floor. his nonstop tip took 9 seconds.
bragg took elevator b from the 3rd floor to the pool on the 11th floor. bragg nonstop trip took 16 seconds.
sarah took elevator c from the 1st floor to the 10th floor. her nonstop trip took 12 seconds.
which elevator is the fastest?
settle this with tables, graphs, and equations.

Brett traveled (0 - 6) = 6 floors down, in 9 seconds. 

                                       6/9 = 2/3 sec per floor.

Bragg traveled (11 - 3) = 8 floors up, in 16 seconds. 

                                        8/16 = 1/2 sec per floor.

Sarah traveled (10 - 1) = 9 floors up, in 12 seconds. 

                                       9/12 = 3/4 sec per floor.

Bragg's trip was the fastest.
Sarah's was the slowest.