An ancient bone contains 69g of carbon and has a decay rate of 45 counts/min. Given carbon's half-life is 5730 years, how old is it? (Assume that the ratio of isotoopes in the atmosphere is Carbon 14/Carbon 12 = 1.3*10^-12 and has remained constant.)

Question

An ancient bone contains 69g of carbon and has a decay rate of 45 counts/min. Given carbon's half-life is 5730 years, how old is it? (Assume that the ratio of isotoopes in the atmosphere is  Carbon 14/Carbon 12 = 1.3*10^-12 and has remained constant.)

anonymous · Answer

the question needs to written correctly and is missing some constants, i think.
i can't really tell when  there is c-12 or c-14