【Question 11】  
$A$ and $B$ are 1200 meters apart. Dacheng starts from $A$ and after 6 minutes, Xiaogong starts from $B$. They meet 12 minutes later. Dacheng walks 20 meters more per minute than Xiaogong. Xiaogong walks $\qquad$ meters per minute.
【Analysis and Solution】
Travel problem.
Dacheng walks 20 meters more per minute than Xiaogong;
Xiaogong $6+12=18$ minutes walks $20 \times 18=360$ meters less than Dacheng; Xiaogong $12+18=30$ minutes walks $1200-360=840$ meters; Xiaogong walks $840 \div 30=28$ meters per minute.