Answer :

iGreen
P = 2(l + w)

Plug in what we know:

960 = 2(l + 150)

Distribute 2:

960 = 2l + 300

Subtract 300 to both sides:

660 = 2l

Divide 2 to both sides:

l = 330

So the length of the longest side is 330 ft.
Let's do it in steps:

1.) We have are aware of the perimeter which is 960 right?
2.) Then we know it is a rectangular shape so it must not be have even sides.
3.) Now,we also know that 2 of the shortest side is 150; so make sure you multiply 150 by 2:
150×2=300
4.) Subtract 960 by 300 which should be 660. Divide 660 by 2 for the longest length sides:
660÷2=330

Your answer should be: 
The length of the longest side each should be 330.

Check by doing this:(formula= side+side+side+side)
So 150+150+330+330=960
Hope this helps!