ich stimme der loesung 10Eurocent zu.

hier mal die mathematische loesungsvariante:

Flasche : F
Sprudel : S
Gesamtpreiss : G

G = 120
G = F + S
=> 120 = F + S

S = F + 100
=> 120 = F + (F + 100)
=> 120 = 2*F + 100 | -100
20 = 2*F | /2
10 = F

Nobody

There are 10 kinds of people.
Those who understand binary code and those who don't.