Question

If a live log contains 200g of carbon-14, how old is buried long that contains 12.5g of carbon-14?

Answer 1

`22920` years

Explanation:

Count how many half-lives have elapsed.

`200rarr100color(white)(sss)` (1)
`100rarr50color(white)(sss)` (2)
`50rarr25color(white)(sss)` (3)
`25rarr12.5color(white)(sss)` (4)

`4` half-lives have occurred. The half-life of carbon-14 is `5730` years.

`5730xx4=22920`