let y = temperature at any time t
at degrees, deg/min
separate variables and solve for y as a function of t ... you have k and you also know y(0) = 90
A cup of coffee was prepared at 90 degree C and left in a room at 20 degree C. Now the temperature is 60 degree and it is cooling at 1 degree/min. How much time has past since the coffee was made.
? netwons law ? dont know how to start it :S