<PRE><B>Question 250313</B>
THe general formula we need is:
{{{A = P*(1/2)^(t/half_life))}}}
I think 1/2 life of carbon is 5280 years. If not use the correct number and these steps.
Also we have lost 12% which means 88%  is till there. So we have
{{{88 = 100*(1/2)^(t/5280)}}}
divide by 100 to get
{{{.88 = (1/2)^(t/5280)}}}
log both sides to get
{{{-.0555173 = (t/5280)*(-.30103)}}}
{{{t = 973.76}}} years</PRE>