Answer:
Sebastian's error = 9 + (-7)
The correct expression for Sebastian's movement = 7 + (-9)
Step-by-step explanation:
Using the Lobby as a reference point
Sebastian's took 7 floors to his room
Hence, Lobby + 7 floors = Sebastian's room
Then, he took 9 floors down to the garage
Hence, Room - 9 floors = Garage
Therefore the total movement for Sebastian = Number of floors taken to his room + Number of floors taken to the garage
= 7 +(-9)
a) Sebastian's error was making the number of movements to his room negative, it is meant to be positive because he took the elevators UP
b) Sebastian's error was making the number of movements to the elevator positive, it is meant to be negative because he took the elevators DOWN to the garage
Hence, the correct expression = 7 +(-9)
