Question

After two half-lives, how much of the original material has decayed?

Answer 1

After two half-lives theres only going to be 25% of the original isotope, 75% of the decay product.

Answer 2

75%

Step-by-step explanation:

100 divided by 2 is 50, and 50 divided by 2 is 25. That's how much material you have left, so 75% of it has decayed.