Respuesta :

Let width be x 
Length; 6+2x 

p=2(l+w) 
7878=2((6+2x)+x)
7878=2(6+3x) 
7878=12+6x 
7878-12=6x 
7866=6x 
7866/=x 
1311=x 

Therefore, the width is 1311 meters, length is (6+2(1311)=2628 meters 

Hope I helped :)