Been at this for hours..

the temperature ,P, of a conductor at time, t, is given by

P=P^0[1-e-^-t/T]

Where P^0 is the initial temperature and T is a constant.

Express T in terms of P,P^0 and t and determine its value when p^0 = 190, P= 20 and t = 40

Any help would be much appreciated...Thanks