How are interference fringes of light analogous to the varying intensity that you hear as you walk past a pair of speakers emitting the same sound?

Explanation:

How are interference fringes of light analogous to the varying intensity that you hear as you walk past a pair of speakers that are emitting the same sound? ... With light, it's the electromagnetic waves alternating between constructive and destructive interference. Whereas with the sounds it is pressure waves in the air.

With light, it's the electromagnetic waves alternating between constructive and destructive interferences. Whereas with the sounds it is pressure waves in the air.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.