You can
put this solution on YOUR website!you need to know the halflife of C-14. It is 5730 years.
Formula for half-life, T is
where y is the "time constant".
We need to figure out the time constant first:
-->
y = 0.000120968 years^(-1)
Right then: exponential decay has a generic formula:
where N is the amount left "now" and
is the original amount.
Now, we are told that the carbon14 has reduced by 62%. So, if there was originally 100g of it, there now is 38g... a reduction of 62%. So, we have:
-->
Working this out gives you 7998.7 years, which is in agreement with your answer, assuming rounding errors and the value of the half life used by the question.
jon.
