1. Movie tickets have three prices: 10 yuan, 15 yuan, and 20 yuan. The class leader bought 30 movie tickets with 500 yuan, among which the 20 yuan tickets are ( ) more than the 10 yuan tickets.
(A) 20
(B) 15
(C) 10
(D) 5
Let the number of movie tickets bought at 10 yuan, 15 yuan, and 20 yuan be $x$, $y$, and $z$ respectively.
According to the problem, we can set up the system of equations:
$$
\left\{\begin{array}{l}
x+y+z=30, \\
10 x+15 y+20 z=500 .
\end{array}\right.
$$
Subtracting (1) $\times 15$ from (2) gives
$$
5(z-x)=50 \Rightarrow z-x=10 \text {. }
$$

This indicates that the number of 20-yuan movie tickets bought is 10 more than the number of 10-yuan movie tickets.
Therefore, the correct choice is C.