Question 948940
I, initial amount
p, amount after time t
t, time in minutes
"amount doubles in 12 minutes."


The first sentence resembles variation.  The second sentence is exponential growth.  


{{{p=Ie^(kt)}}}
Find k.
{{{2000=1000e^(k*12)}}}
{{{2=e^(12k)}}}
{{{ln(2)=12*k*ln(e)}}}
{{{ln(2)/12=k}}}
{{{highlight_green(k=0.05776)}}}


How much time from 1000 to 10000?
{{{p=Ie^(0.05776*t)}}}
{{{10000=1000*e^(0.05776t)}}}
{{{10=e^(0.05776t)}}}
{{{ln(10)=0.05776t}}}
{{{t=ln(10)/0.05776}}}
t=40 minutes.