The perimeter is given by:
[tex]\begin{gathered} P=2w+2l \\ where \\ w=width \\ l=length=2w-6 \\ so\colon \\ 48=2w+2(2w-6) \\ 48=2w+4w-12 \\ 48=6w-12 \\ solve_{\text{ }}for_{\text{ }}w \\ 6w=60 \\ w=\frac{60}{6} \\ w=10 \end{gathered}[/tex]So:
[tex]\begin{gathered} l=2(10)-6 \\ l=14 \end{gathered}[/tex]width = 10m
l = lenght = 14m
