A steel rod of temperature 600oF is immersed in a large vat of water at temperature 75oF. At the end of each minute, its decrease in temperature is 30% of the difference between the water temperature and the temperature of the rod at the beginning of the minute.
(a) Give the difference equation for yn, the temperature of the rod after n minutes.
(b) What is the temperature after 2 minutes?
(c) When will the temperature drop below 80o F?