Question 924347
Start with a general exponential decay equation and solve for for t and for k.


A generalized exponential decay equation:  {{{y=b*e^(kt)}}} using assigned variables,
y, amount at any time t
b, initial amount at t=0
k, a rate constant which will be negative
t, passage of time in day


SOLVE THE DECAY EQUATION SYMBOLICALLY FOR THE TERM kt:
TAKE LOGs OF BOTH SIDES, A FEW STEPS NOT SHOWN HERE BUT SHOULD STILL BE UNDERSTOOD (HOPEFULLY):
{{{ln(y)=ln(b)+ln(e^(kt))}}}
{{{ln(y)=ln(b)+kt}}}
{{{kt=ln(y)-ln(b)}}}
{{{highlight_green(kt=ln(y/b))}}}; first use this to find k from the first  two sentence.  Use the green outlined equation again to find half-life.