Question

Two sound waves traveling in the same medium interfere with each other. The compression of one wave falls on the compression of the other wave. What can you say about the resultant sound?
The resultant sound will be louder than the individual sound waves.
The resultant sound will be lower than the individual sound waves.
The resultant sound will have the same loudness as the individual sound waves.
The resultant sound will not be heard at all.

Answer 1

The resultant sound will be louder than the individual sound waves, superposition is the technique you use here. If both waves are doing the same thing they add onto each other, if they are doing opposite things they cancel out and anything in between you need to calculate.

Answer 2

The answer is A.
The wave undergoes superposition due to the compressions falling on each other.
This makes the amplitude of the resultant wave increase, and therefore will make a louder sound.

And

Because simply constructive superposition takes place.
As two waves come together if each have an amplitude of X, when they compress together they get an amplitude of 2X. So when amplitude increases Loudness increases.