An elevator started on the first floor, went up 18 floors, then came down 11 floors and went back up 16. 1 + 18 - 11 + 16
1 - 18 - 11 + 16
1 + 18 + 11 - 16
1 - 18 + 11 - 16

1+18-11+16

Step-by-step explanation:

if the elevator went up it will be plus but if the elevator came down it will be minus and then you will get 1+18 because it went up and then it go down 11 floor and it will be 1+18-11 and then it went up again 16 floor so the last answer will be 1+18-11+16

the answer is 31.27mph