Two identical violin strings, when in tune and stretched with the same tension, have a fundamental frequency of 440.0 Hz. One string is retuned by adjusting its tension. When this is done, 1.5 beats per second are heard when both strings are plucked simultaneously.
(a) What are the possible fundamental frequencies of the retuned string?
(b) By what fractional amount was the string tension changed if it was (i) increased and (ii) decreased?