the answer is 26 grams
Explanation
We can determine the amount of a radioactive isotope remaining after a given number half-lives by using the following expression:
[tex]\text{amount remaining= Initial amoutn (}\frac{1}{2})^n[/tex]where n is the time
Step 1
Let
[tex]\begin{gathered} \text{ Initial amount= 210 grams} \\ n=\text{ 3} \end{gathered}[/tex]replace
[tex]\begin{gathered} \text{amount remaining= Initial amoutn (}\frac{1}{2})^n \\ \text{amount remaining= 210 (}\frac{1}{2})^3 \\ \text{amount remaining= 210 (}\frac{1}{8})^{} \\ \text{amount remaining= }26.25 \\ \text{rounded} \\ \text{amount remaining=}26 \end{gathered}[/tex]so, the answer is 26 grams
i hope this helps you
