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kym02
One gram of a living plant containing Carbon-14, decays at about 16 disintegrations per minute. It is found that one gram of a dead plant decays at 1 disintegration per minute. The half-life of Carbon-14 is about 5500 years. Calculate the probable age of the plant. Thank you.
1 dpm is about 4 half lives from the start = 16 dpm. (16-8-4-2-1). Thus, 4 half-lives X 5500 years = about 22,000 years.
1/16 rate is (1/2)^n where n = # half-lives. n = 4, so 4 x 5500 = 22,000 years, as @LunarSolstice just found.