If a cricket chirps 140 times in one minute the temp is 72F because 140/60 is 2.333.. which is the chirps per second. you multiply that by 15 to find the number of chirps in 15 seconds which is 35. 35+37 is 72. If the temp is 60F then you subtract 37 to find the number of chirps in 15 seconds which is 23. you do 23×4 since that will find the number of chirps in one minute, and you get 92. you do 92×5 to find the number of chirps in five minutes and get 460 chirps per minute