Answer: It was obtained 8515 years ago
Explanation:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) to find the rate constant:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
b) for completion of 36% of reaction
t = 8515 years
The time was 8515 years.