answer - 6 meters and the width is 3 meters!
why?
2 ( length + width )
18 meters = 2 ( width + 3 + width )
divide both sides by 2
9 = width + 3 + width
9 = 2 width + 3
subtract 3 on both sides.
9 - 3 = 2 width + 3 - 3
6 = 2 width
divide by 2 on both sides.
3 = width
width = 3
putting in (1)
length = width + 3 = 3 + 3 = 6
we see that
length = 6 meters
width = 3 meters
hope this helps!!!!