Question

The half-life of carbon-14 is 5,730 years. How many grams of parent material will remain from a 100-gram sample of carbon-14 after 2 half-lives?

75

6.25

12.5

25

Answer 1

half-life is the time that takes for a sample loose half of inicial size.
we can make a equation for that:
\[finalweight = sampleweight \div 2^{n}\]
where n is the number of half-lifes that have occurred

So, for this problem, we have:
\[100\div2^{2}\] = 25 gram