Answer:
the length of RS to the nearest tenth of a foot is 240.6ft
The bottom rectangle is 52 ft by 27 ft.
The top rectangle is 30 ft by 17 ft (calculated as 57 ft - 27 ft - 13 ft = 17 ft).
The connector rectangle is 13 ft by 9 ft (calculated as 30 ft - 21 ft = 9 ft).
total area = 52 ft * 27 ft + 30 ft * 17 ft + 13 ft * 9 ft
total area = 1404 ft^2 + 510 ft^2 + 117 ft^2
total area = 2031 ft^2
weight = 2031 ft^2 * 12 lb/ft^2
weight = 24,372 lb
After having done this on paper:

We want to isolate the variable, and the first step is to subtract the 8.

Since the <em>n</em> is being multiplied by 3, and that = 8, we can multiply both sides by 3.
<em>n</em> = 24
Let me know if this helped you understand better.
Also, you can check this by substituting in 24 for <em>n</em>.
I got letter A when I tried it