Question

4 PTS

What percent of uranium-235 remains after 1420 million years?

A)

12.5%

B)

25%

C)

40%

D

75%

Answer 1

Answer:

B) 25% but to be exact 24.7%

Explanation:

The halflife of 235U is 704 million years. 1420 million years is approximately two halflives, so about 24.7% would be remaining.