Question

In how many years will you have 50g of K-40 left?

Answer 1

Potassium-40, for example, decays into Argon-40 with a half-life of 1.25 billion years, so that after 1.25 billion years half of the Potassium-40 in a rock will have become Argon-40

Answer 2

So the answer is 1.25 billion years :)

Answer 3

my teacher has 1.3 billion years..and i dont know where she got the answer.

Answer 4

She rounded to the nearest tenth. 1.25 is 1.3 since the hundredths is 5 or higher