1. (10 points) In a class of 36 people, a total of 50 pencils were bought. Some people bought 1 pencil, some bought 2 pencils, and some bought 3 pencils. If the number of people who bought 1 pencil is twice the number of the rest, then the number of people who bought 2 pencils is $\qquad$
【Analysis】The number of people buying 1 pencil is twice the number of the rest, which means the total number of people in the class is $1+2=3$ times the number of the rest. First, according to the meaning of division, find out the number of people buying 2 pencils and 3 pencils, then set the number of people buying 2 pencils as $x$, and express the number of people buying 3 pencils using $x$. Finally, based on the total number of pencils bought $=$ number of people $\times$ number of pencils bought, express the total number of people buying pencils using $x$, and set up an equation according to the total number of pencils being 50. Solve according to the properties of equations.

【Solution】Solution: $36 \div(1+2)$
$$
\begin{array}{l}
=36 \div 3 \\
=12 \text { (people); }
\end{array}
$$

Let the number of people buying 2 pencils be $x$ people
$$
\begin{aligned}
12 \times 2 \times 1+2 x+(12-x) \times 3 & =50 \\
24+2 x+36-3 x & =50 \\
60-x+x & =50+x \\
60-50 & =50+x-50 \\
x & =10 ;
\end{aligned}
$$

Answer: The number of people buying 2 pencils is 10.
The answer is: 10.