Two piano strings are supposed to be vibrating at $220$ Hz

$,$ but a piano tuner hears three beats every $3\mathrm{.}1$ s

when they are played together.

Part A

Part complete

If one is vibrating at $220$ Hz

$,$ what must be the frequency of the other $($is there only one answer$)?$

Express your answer using four significant figures. If there is more than one answer, enter them in ascending order separated by commas.

f$2$

$=$

$219\mathrm{.}0,221\mathrm{.}0$

Hz

Previous Answers

Correct

Part B

By how much $($in percent$)$ must the tension be increased or decreased to bring them in tune?

Express your answer using two significant figures. If there is more than one answer, enter them in ascending order separated by commas.