so, start floor = x
x + 7 - 9 - 4 + 8 - 2 = 14
x = 14
the elevator started on the 14th floor.
to verify: 14 + 7 = 21 - 9 = 12 - 4 = 8 + 8 = 16 - 2 = 14
the answer should be the third option
Suppose the integers are n , n+2 , n+4 and n+6.
84=n+(n+2)+(n+4)+(n+6)=4n+12.
Subtract 12 from both ends to get.
72=4n.
Divide both ends by 4 to get.
n=18.
So the integers are: 18 , 20 , 22 , 24.
