A wooden artifact from an ancient tomb contains 70% of the carbon-14 that is present in living trees. How long ago was the artifact made? (The half-life of carbon-14 is 5730 years. Round your answer to the nearest whole number.)

Answer 1

0.5^(t/5730) = 0.7
t/5730 * log .5 = log .7
t/5730 = 0.5145
t = 2949

Answer 2

A wooden artifact from an Ancient tune contains 80% of the carbon – 14 that is present in living trees. How long ago was the artifact made? (The half-life of carbon-14 is 5730 years. Round your answer to the nearest whole number.)