Question 966326
{{{y=Ie^(kt)}}} as a general model.


Find k.
{{{ln(y)=ln(I)+ln(e^(kt))}}}
{{{ln(y)-ln(I)=kt}}}
{{{k=(1/t)ln(y/I)}}}


The VALUE of k:
{{{ln(35/20)/4}}}
{{{k=ln(7/4)/4}}}


Do the rest...