Question 143487
Let the width = w. 
The length is given as "10 feet more than twice the width". So  {{{l = 10+2w}}}

The perimeter is givenb as 260 feet. You know the perimeter of a rectangle is
{{{P = 2w + 2l}}}
{{{260 = 2w + 2(10+2w) }}}
{{{260 = 2w + 20 + 4w }}}
{{{260 - 20 = 2w + 4w }}}
{{{240 = 6w }}}
{{{40 = w }}}

Check your answer.
If w = 40 , then length = 10+80 = 90.

Is 2*40 + 2+90 = 260??