We can find the beat frequency using the following formula:
[tex]_{\text{ }}f_{beat}=|f1-f2|[/tex]A.
Let:
f1 = 341 Hz
f2 = 347 Hz
So:
[tex]_{\text{ }}f_{beat}=|341-347|=|-6|=6Hz_{}[/tex]B.
Let:
f1 = 1003Hz
f2 = 998Hz
So:
[tex]_{\text{ }}f_{beat}=|1003-998|=|5|=5Hz_{}[/tex]