Solution :
For the bigger rectangle
Width of bigger rectangle = W
Length of bigger rectangle, L = 2W
For the smaller rectangle
Width , w = W+4
Length, l = L = 2W
Area, a =120

Now we know,
Area = length x width






We get, either
(rejecting)
or

∴ length of the bigger rectangle,

= 2(6)
= 12 m
Length of the smaller rectangle,

= 2(6)
= 12 m
Hence, the length of the two gardens is 12 m.