Carbon-14 has a half-life of 5730 . In a plant fossil, you find that the has decayed to 1/32.0 of the original amount. How long ago was this plant alive?

Answer 1

k = 0.693/t_1/2
Solve for k.

ln(No/N) = kt
You can make No any convenient number. I would pick 64/
N is No x (1/32) = ? for No = 64 that is 2.00
k from above.
Solve for t in years.

Answer 2

17190 years