Solution: Let Xiao Gang have X copies.

3X-X= 16 8+ 16=24 sheets.

Solution: 2X= 16

2X/2= 16/2 A: Xiao Gang 8, Xiao Ming 24.

X=8

2.

Solution: Let's leave for X hours.

(75+85)X=576

Solution: 160X=576 A: I walked for 3.6 hours.

160 x/ 160 = 576/ 160

X=3.6