Biologists have found that the number of chirps that crickets of a certain species make per minute is related to the temperature. The relationship is very close to linear. At 68°F, those crickets chirp about 124 times a minute. At 80°F, they chirp about 172 times a minute.
(a) Find the linear equation relating Fahrenheit temperature F and the number of chirps c.
(b) If you count chirps for only 15 seconds, how can you quickly estimate the temperature?