Answer:
Answer is The 2nd elevator
Step-by-step explanation:
1st Elevator
5+12 = 17
17- 8 = 9
so 1st elevator ends on floor 9th
2nd Elevator
21-10 = 11
11+9 = 20
2nd Elevator ends on floor 20th
so therefore the elevator that ends on the higher floor is the 2nd elevator