Sulochana is right, "raten" can also have the meaning "to guess". Apart from that, "beraten" is normally used in a more 'formal' situation where you're having a dedicated advisor (Berater), e.g. a bank or insurance employee or someone counseling a politician. Note that the verb patterns are different too: – jemandem etwas raten – jemanden beraten

Raten means guess and advice beraten means advice