Question

A piano tuner strikes a tuning fork at the same time he strikes a piano key with a note of a similar pitch. If he hears 3 beats per second, and the tuning fork produces a standard 440 Hz tone. Then what was the frequency produced by the struck piano string? a 434Hz or 446Hz b 437 Hz c 437Hz or 443 Hz d 443 Hz

Answer 1

The frequency produced by the string could be 437 Hz or it could be 443 Hz.

The frequency of the beats ... 3 Hz ... tells the piano tuner that
the difference between the fork and string frequencies is 3 Hz,
but it doesn't tell her which one is higher or lower.