Answer:
The first two.
Explanation:
See that L is 600mm MORE than W.
From there, you can note that L = W+600
or rearrange the formula and get W= L-600
Then, see that the perimeter of a flag is 2L + 2W
(Because there are two four sides to a rectangle, 2 width, 2 length)
It must total to be 5 meters, or 5000mm
Thus,
2L + 2W = 5000