Answer:
[tex]f_{frequency}=483Hz[/tex]
Explanation:
Let f is frequency of of the guitar string
Frequency of tuning fork is given 487 Hz
Beat frequency is difference frequencies of guitar string and the tuning fork
It could be
(f - 487Hz)
or
(487Hz-f)
As it is mentioned that as the frequency of guitar string increases the beat frequency decreases
So the beat frequency is given as
[tex]f_{frequency}=(487Hz-f)\\f_{frequency}=(487-4)\\ f_{frequency}=483Hz[/tex]