Math Help - Solve by seperation of Variables

1. Solve by seperation of Variables

A body at an unknown temperature is placed in a room which is held at a constant temperature of F. If after 10 minutes the temperature of the body is F and after 20 minutes the temperature of teh body is , find the body's initial temperature.
I have no idea to even begin to start the problem. I just don't understand how i would write the initial equation for it.

2. Do you know Newton's Law of Cooling?

http://en.wikipedia.org/wiki/Convect...law_of_cooling

You don't need the area to solve this problem though