posted by gary .
An artifact was found and tested for its carbon-14 content. If 75% of the original carbon-14 was still present, what is its probable age (to the nearest 100 years)? (Carbon-14 has a half-life of 5,730 years.)
amount = initial (.5)^(t/5730)
.75 = 1 (.5)^(t/5730)
log .75 = (t/5730) log .5
t/5730 = log .75/log .5 = .415...
t = 2378.16
age is about 2400 years to the nearest century