6. A wooden boat is found buried beneath the ocean floor. Scientists believe that timbers making up the boat had 8 g of carbon-14 in them when alive. They now have 2.3 g of carbon-14. How old is the boat if the half-life of carbon-14 is 5715 years?
2. In 40 days, the number of radioactive nuclei decreases to one-sixteenth the number present initially. What is the half-life (in days) of the material?