In[]:=
data={{0,0},{10,102},{20,186},{30,228},{40,240},{50,243},{60,228},{70,227},{80,210},{90,192},{120,144},{150,102},{180,66},{240,30},{300,18},{360,6}};
In[]:=
temp[t_]:=a*(Exp[-k1*t]-Exp[-k2*t])​​
In[]:=
substs=FindFit[data,temp[t],{a,k2,k1},t]
Out[]=
{a866.073,k20.0300234,k10.0137621}
In[]:=
funct[t_]=temp[t]/.substs
Out[]=
866.073(-
-0.0300234t

+
-0.0137621t

)
In[]:=
Show[ListPlot[data,PlotStyle->Green],Plot[funct[t],{t,0,480}]]
Out[]=
In[]:=
temp2[t_]:=a*(Exp[-0.01376208490662561*t]-Exp[-k2*t])
In[]:=
funct2[t_]=temp2[t]/.FindFit[data,temp2[t],{a,k2},t]
Out[]=
339.024(-
-9129.04t

+
-0.0137621t

)
In[]:=
temp3[t_]:=a*(Exp[-k1*0.1*t]-Exp[-k2*t])
In[]:=
funct3[t_]=temp3[t]/.FindFit[data,temp3[t],{a,k1,k2},t]
Out[]=
247.865(-
-374.178t

+
-0.00503781t

)
In[]:=
Show[ListPlot[data,PlotStyle->Green],Plot[funct2[t],{t,0,480},PlotRange->Full],Plot[funct3[t],{t,0,480},PlotStyle->Gray],PlotRange->Full]
Out[]=
In[]:=
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​