If 118m is the perimeter=2(length+width)=2(2w+8+w)=118; 2(3w+8)=118; 3w+8=59 and 3w=51 so w=17 and length=2w+8=34+8=42.
The simplest answer is based on the assumption that 118m is the perimeter: length=42m, width=17m.
Check: perimeter=2(42+17)=2*59=118". OK.