Question 924217

a) Find the amount present after {{{12}}} days. 
I think I got this one. 

{{{A(12)=600e^(-0.5*12)}}}
{{{A(12)=1.487g}}}----you got this one

b)find the half-life of the material
 

{{{300=600e^(-0.5t)}}}

{{{300/600=e^(-0.5t)}}}

{{{.5=e^(-0.5t)}}}  

{{{ln(.5)=ln(e^(-0.5t))}}}

{{{ln(.5)=(-0.5t)ln(e)}}}......{{{ln(e)=1}}}

{{{ln(.5)=-0.5t}}}

{{{-0.693147=-0.5t}}}

{{{-0.693147/-0.5=t}}}

{{{t=1.386294}}}