Question 1088677
{{{y=a*b^x}}}


{{{(1/2)=1*b^9}}}

{{{b^9=1/2}}}

{{{9*log((b))=log((1/2))}}}

{{{log((b))=(1/9)log((1/2))}}}


{{{log((b))=-0.03345}}}

{{{highlight_green(b=0.926)}}}

This means,  about 7.4% decrease per day