You have a tuning fork of unknown frequency. When you ring it alongside a tuning fork with known frequency of 360 Hz, you hear beats at a frequency of 10 Hz. When you ring it alongside a tuning fork with known frequency of 347 Hz, you hear beats at a frequency of 3 Hz. What is the unknown frequency?

Answer 1

You hear the difference so

1. could be 370 or 350

2. could be 350 or 344

so it is 350

Answer 2

You better google "beat frequency" !