Question 1128843
{{{y=240*(1-0.132)^x}}}


{{{highlight(y=240*0.868^x)}}}



-----
C)If Ethan has 40 mg of caffeine left in his body, how many hours have elapsed
-----


{{{240*0.868^x=40}}}

{{{0.868^x=4/24}}}

{{{0.868^x=1/6}}}

{{{log((0.868^x))=log((1/6))}}}

{{{x=(1/log((0.868)))*log((1/6))}}}

about 12.6 hours