Let the width be W meter

so, length= 2W-3

meter

Perimeter of a recatngle= 2(Length + width)

so, perimeter = 2[(

2W-3) + W] = 2[ 3W -3] = 6W

-6

given, perimeter = 18 meter

so, 6W-6=18

or6W= 18+6

or, 6W =

24

or, W = 24/6 =4

so, the width of the rectangle = 4 meter