Question

Two speakers are wired to emit identical
sounds in unison. The wavelength in air of
the sounds is 6 m.
Do the sounds interfere constructively or
destructively at a point 10 m from both speakers?
1. Destructively
2. Neither
3. Constructively

Answer 1

At the same distance from each speaker, they interfere constructively. This assumes that they are wired "in phase".

Answer 2

Constructively