This exercise uses the radioactive decay model.

A wooden artifact from an ancient tomb 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.)
? yr

I am having trouble with this question as well can anybody help me?

1 answer

general equation
amount = a (1/2)^(t/5730) , where t is in years

.8 = 1 (1/2)^(t/5730)
.8 = 1 (.5)^(t/5730)
log .8 = (t/5730) log.5
t/5730 = log.8/log.5
t = 5730(log.8/log.5) = appr 1844.6 years