I have asked a similar question before but i realised i was asking the wrong thing...........

a. for the equation dT/dt= -k(T-8) what is the upper or lower limit of k if the temperature (T) is to never fall below T=15 ......... when t=0, T=16

b. if k=0 what does this say about the insulation properties of k?

THANK YOU!!!!!!!!!!!