You have to solve this algebraicly.
To do this set up the proportion and add x to each term.
You get 4x and 7x
Set this equal to 33
4x+7x=33
Combine like terms and get 11x=33
Divide by 11
x=3
Now go back to 4x and 7x
Multiply them by x and get 12(4×3=12) and 21(7×3=21)
One group is 12 and the other is 21.