Answer
$-1.9 \%$.
Work Step by Step
The frequency is related to the wavelength, $f=\frac{v}{\lambda}$.
The speed of sound changes as a function of temperature; that is the first equation in Chapter 12.
Find the change in frequency.
$$\Delta f=f_{11} – f_{22} = \frac{331+(0.60)(11)}{\lambda}-\frac{331+(0.60)(22.0)}{\lambda}$$
We assume that the length of the pipe (and the resonant wavelength) did not change.
Now find the percentage change.
$$\frac{\Delta f}{f_{22}}=\frac{331+(0.60)(11)}{ 331+(0.60)(22.0)}-1=-1.92\times 10^{-2}=-1.9 \%$$
