Question 1032365
Loss of 25% every 40 minutes is the same as KEEPING 75% every 40 minutes.
{{{highlight_green(Q=A*(0.75)^t)}}}


You are interested among other questions, in the half-life, and you can use  {{{t/40}}}
as the exponent.  NOW,  {{{Q=A(0.75)^(t/40)}}}  uses t to count MINUTES, so the form of the
equation is a little different.   Half life would be like so...


{{{(1/2)=(0.75)^(t/40)}}}
Choosing natural log,
{{{ln(0.75^(t/40))=ln(1/2)}}}
{{{(t/40)*ln(0.75)=ln(1/2)}}}
{{{t=40*ln(1/2)/ln(0.75)}}}
{{{t=40(ln(1/2)/ln(3/4))}}}
{{{t=40(0.69314/0.28768)}}}
{{{highlight(t=96.4)}}}-------------half life in minutes.