OK here we go!…
Start on the third line.. Three windows
is 18 so each window is 6
Line two.. five tires = 25.. so each tire is 5.
First line. There are three trailers, 12 tires and three windows
The 12 tires on the first line total 60.
The three windows
on the first line equal 18.
The total for windows and tires on the first line is 78.
Line one total is 90… minus 78 for the tires and windows leaves 12 for the three trailers.
Or 4 for each trailer.
Trailer = 4
Tire = 5
Window = 6
Now for the final line.. but note that there is no window and only two tires on the trailer! So… on the last line the trailer is one Trailer (4) + two tires (10) = 14
Now on the last line we have one tire (5) + trailer with two tires and no window (14) times one window (6).
... 5 + 14 x 6
Assuming algebraic operator precedence, first we do 14 times 6 = 84, then 84 + 5 = 89
I have edited this a bunch so maybe I will be quoted with a different answer but its late so.. final answer: 89