Question 1071963
A:
Find k, given half-life 5730 years.
{{{1/2=1*e^(k*5730)}}}

{{{ln(1/2)=ln(e^(k*5730))}}}

{{{ln(1/2)=5730*k}}}

{{{k=ln(1/2)/5730}}}

{{{highlight(k=-0.000121)}}}


B:
How old is bone if 65% of original C-14 remains?
{{{0.65=1*e^(-0.000121*t)}}}

{{{ln(0.65)=ln(e^(-0.000121t))}}}

{{{-0.000121t=ln(0.65)}}}

{{{t=ln(0.65)/(-0.000121)}}}

{{{highlight(t=3560)}}}, years