An artifact was found and tested for its carbon-14 content. If 78%
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.)

The answer to the question is 2500. I got the answer by using ratios. first I put the percentage that the amount would be decreased over 5,730 years. Next I set it equal to the amount that would be decreased when 78% was present which would be 22%. Then I cross multiplied and found the answer to be 2521.2 which rounded equals 2500. the equation I used was 50/5730=22/x. I hope this helps.