Yíbàn yíbàn ba.
一半一半吧。
Fifty-fifty.
Notes:
一半(Yíbàn): half
吧(ba): model particle word which indicates the whole sentence is a suggestion.
Example:
A:这个蛋糕怎么分?
Zhè ɡe dànɡāo zěnme fēn?
How do we divide this cake?
B:一半一半吧。
Yíbàn yíbàn ba.
Fifty-fifty.