There is an established correlation between the number of chirps of a cricket and temperature. The function is
ln C = -6713.2 / T + 25.868
Where c is the number of chirps per min and T is the temperature in K
We are given
T = 22 C + 273 = 295K
Solving for C
ln C = -6713.2 / 295 + 25.868
C = 22.45 chirps/min
In 21 seconds, the number of chips is
22.45 chirps / min (1 min/60 s) (21 s) = 7.86 chirps
