Answer:
I may have misubderstood the question, so review carefully.
width = 380 m
length is 420 m
Explanation:
Let w and l stand for the width and length of the stadium.
We are told that w = l - 40 m
We also learn that l = 420 m
w = l - 40 m
w = (420 m) - 40 m
width = 380 m
length is 420 m