Question

You find a fossil that you think is about 350 million years old. You decide to use 235U to date a volcanic ash bed just below the key specimen. The half-life of 235U is 700 million years. If you are correct, what approximate percentage of the original 235U would you expect to remain in your sample?

Answer 1

I would expect that the sample has only 50% of the original 235 U.

Step-by-step explanation:

That is because 235 U has a half-life of 700 million years and I expect that my sample be 350 million years old. 350 is half of 700.