An anthropologist finds bone that her instruments measure it as 0.526% of the amount of Carbon-14 the bones would have contained when the person was alive. How long ago did the person die?

At year after death, C = Co * (1/2) ^ (y/5730)

C = Co*0.00556

Co*0.00556 = Co * (1/2) ^ (y/5730)

0.00556 = (1/2) ^ (y/5730)

ln (0.00556) = (y/5730) * ln (0.5)

y/5730 = ln (0.00556) / ln (0.5)

y = 5730*ln (0.00556) / ln (0.5)

y = ~ 42921.7

y = ~ 43000 years