Question 276583
I will answer your first question.  If you have more than one, you should post them separately.

If we call the length L and the width W, then remember that perimeter is:
{{{P=2L+2W}}}
We have that the length is 15 more than twice the width, so we can represent length by 2W+15.  Thus we have:

{{{120=2(2W+15)+2W}}}
{{{120=4W+30+2W}}}
{{{120=6W+30}}}
{{{90=6W}}}
{{{15=W}}}

So the width is 15 feet.  Thus the length would be 2(15)+15=45 feet.