Answer:
No, they are not equivelent.
Explanation:
If we solve both of them :
3:6 = 3/6
3/6 = 1/2
1/2 = 1:2
6:3 = 6/3
6/3 = 2/1 (just 2!)
2/1 = 2:1
So, they aren't the same because they aren't the same fraction and they don't simplify to the same answer :)
Let me know if you need more of an explanation!