Question

A specimen of charcoal found at stonehenge contains 63% as much carbon-14 as a sample of present-day charcoal. what is the age of sample

Answer 1

First you need the half-life of carbon 14 - which is 5,730years

Answer 2

Next we need a formula
elapsed time = half-life * log[(beginning amount / ending amt)] / log 2

Answer 3

Time = 5,730 years * log (1/.63) / .30103
Time = 5,730 * (0.2006594505 / .30103)
Time = 3,820 years