Urgent mathematical problems

After the two groups transferred the same number of people, the difference between the two groups remained unchanged:

Art: Calligraphy = 28: 16 = 7: 4 = 14: 8.

Art: Calligraphy = 3: 1 = 9: 3

Number of people per serving: (28- 16)/( 14-8)=2 (person)

Two groups: 2x( 14-9)= 10 (person)