Answer:
The unknown frequency is either 438 Hz or 442 Hz.
Explanation:
The frequency of a beat heard when two sounds with frequencies f₁ and f₂, are played simultaneously, is simply the difference between two frequencies.
b = |f₁ - f₂|
b = 2 Hz
f₁ = 440 Hz
f₂ = ?
440 - f₂ = 2 or 440 - f₂ = -2
f₂ = 438 Hz or 442 Hz
The unknown frequency is either 438 Hz or 442 Hz.
Hope this Helps!!!