Question

If a note x of unknown frequency produces 8 beats/sec, with a source of 250 Hz and 12 beats/sec with a source of 270 Hz, the frequency of unknown source will be:

• A. 258 Hz
• B. 242 Hz
• C. 262 Hz
• D. 282 Hz

Answer 1

The correct option is A 258 Hz

Since source of frquency $X$ gives $8$ beats per second with frequency $250Hz$. It's possible frequency are $258$ or $242$. As source of frequency $X$ gives $12$ beats per second with a frequency $270Hz$ It's possible frequencies $282$ or $258$ hz.

The only possible frequency of $X$ which gives $8$ beats with frequency $250Hz$ also $12$ beats per second with $258$ Hz..

Hence the option $A$ is the correct answer.