Question 363543
The radioactive element carbon-14 has a half-life of 5750 years.
 The percentage of carbon-14 present in the remains of plants and
 animals can be used to determine age. 
How old is a skeleton that has lost 40% of its carbon-14?
Note: Do not round any numbers during your calculation.
:
Using the half-life formula: A = Ao*2^(-t/h)
Where
A = resulting amt after t yrs
Ao = initial amt
t = time
h = half-life of substance
:
Assume the initial amt = 1, remaining amt after t yrs = .6
:
1*2^(-t/5750) = .6
using nat logs
{{{-t/5750}}}ln(2) = ln(.6)
{{{-t/5750}}} = {{{ln(.6)/ln(2)}}}
{{{-t/5750}}}ln(2) = -.736955942
t = -5750 * -.736955942
t = 4,237.55 yrs