You can
put this solution on YOUR website!Let the width of the paths be x meters.
The combined area of the two paths can be written:

The subtraction of

takes into account the overlapping area of the paths' intersection which would otherwise be counted twice. So now you need to solve the quadratic equation:

Factor.

Apply the zero products principle.

and/or

If

then

Discard this solution as the path can't be wider than the garden.
If

then

This solution is valid.
The width of the path is 5 meters.