Yeah lol I just got a guest answering like that
"the answer is 18"
Like.... ok i guess?
Btw: (I'm not bothering with latex :p )
If your load is x, and one of your neighbors trucks can carry y,
Then we have:
x >= y+600
x <= 1/3(4y)
y+600 <= x <= 1/3(4y)
If we equate y+600 = 1/3(4y), we get y=1800 (the max value for y)
And our upperbound (1/3(4y)) is 2400
The greatest load your truck can carry is 2400 pounds :]
(If that is incorrect, I think there is no real solution, all values of x and y will satisfy this equation.)