x is the number of athletes on first team originally ( x > 12, x ∈ Nˣ )
y ----------------------------------------second------------------( y ∈ Nˣ )
The ratio of athletes in the two teams is 3:2
⇒
(1)
After 12 athletes move from first team to second, the ratio is 5:4
⇒
(2)
(1),(2) ⇒

So: The first team originally has 162 numbers and the second team originally has 108 numbers
ok done. Thank to me :>