Let's break down the problem step-by-step:

1. Given Information:

   • There are twice as many girls as boys on the yearbook staff.
   • At a staff meeting, the percentage of girls attending was twice the percentage of boys attending.

2. Let:

   • $B$ represent the number of boys on the staff.
   • $G$ represent the number of girls on the staff.

   According to the problem, $G = 2B$ (twice as many girls as boys).

3. Let:

   • $x \%$ be the percentage of boys attending.
   • $2x \%$ be the percentage of girls attending (since the problem states that the percentage of girls attending was twice that of boys).

4. Determine the actual number of boys and girls attending the meeting:

   • Number of boys attending = $\frac{x}{100} \times B$
   • Number of girls attending = $\frac{2x}{100} \times G$

5. Substituting $G = 2B$ into the expression for the number of girls attending:

   • Number of girls attending = $\frac{2x}{100} \times 2B = \frac{4x}{100} \times B$

6. Total number of people attending the meeting:

   • Total attending = $\frac{x}{100} \times B + \frac{4x}{100} \times B = \frac{5x}{100} \times B$

7. Percentage of those attending who are boys:

   • Percentage of boys = $\frac{\frac{x}{100} \times B}{\frac{5x}{100} \times B} \times 100$
   • Simplifying this expression gives: $\frac{x}{5x} \times 100 = \frac{1}{5} \times 100 = 20\%$

Final Answer: The percentage of those attending who were boys is 20%.

Would you like any further explanation, or do you have any additional questions?

Here are five related questions:

1. What is the relationship between ratios and percentages in problem-solving?
2. How do you convert between fractions, decimals, and percentages?
3. How can you check if a problem involves direct or inverse proportion?
4. In a similar scenario, how would you handle cases where there is an uneven distribution of students?
5. What role does algebra play in setting up and solving word problems?

Tip: Always set up variables and equations to translate word problems into mathematical expressions.