A 17.4985 g sample of petrified wood was found in a petrified forest. The sample showed a 14C activity of 7.66 decays/min. How long has the tree been dead? The half-life of carbon-14 is 5730 years and freshly cut wood contains 6.5 1010 atoms/g of 14C and there are 365.25 days in a year.

1. 26016.4

2. 27211.5

3. 26623.5

4. 29192.2

5. 30212.4

6. 21487

7. 28453

8. 25010.2

9. 30515.7

10. 21925.1

Answer in units of y.