There are numbers whose sum is 50. Three time the 1st is more than twise the second.? please solve

I think you are missing something here.

"Three time the 1st is .??.. more than twice the second

the way it stands:
one number --- x
the other ----- 50-x

3(x) > 2(50-x)
3x > 100 - 2x
5x > 100
x > 20

So possible solutions:

If our domain is the set of whole numbers
21,29
22,28
23,27
....
49, 1
50 , 0
if we allow integers, then
51, -1
52, -2
... to infinity