This question involves the concept of the beat frequency.
The possible frequencies of the guitar string could be "445 Hz" (or) "435 Hz".
When two sounds with a very minor difference in their frequency are played, they produce a frequency equal to the absolute value of the difference between their frequencies. This frequency is known as beat frequency.
[tex]f_b=|f_1-f_2|[/tex]
where,
Therefore,
5 Hz = |440 Hz - f₂|
f₂ = 440 Hz ± 5 Hz
f₂ = 445 Hz (OR) 435 Hz
Learn more about beat frequency here:
https://brainly.com/question/10306260