Nucleus: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Nucleus. Understanding the underlying formula is key to arriving at the correct answer below:

Let the fractional abundance of $^{10}B$ be $x$ and $^{11}B$ be $1-x$. The atomic weight is $10x + 11(1-x) = 10.81$. Solving this yields $11 - x = 10.81$, so $x = 0.19$. The ratio is $0.19 : 0.81 = 19 : 81$.