This problem is a variation of a group problem. the basic formul is Group 1 +Group 2 - Both + Neither = total but here you ahve three groups (English, Spanish and German)and a neither as well as additional restrictions. Because you can't have anyone with all three languages and if they speak German they must speak English you have the formula
Eonly+ES+GE+Sonly + neither = 200
The stem tells you that Sonly=70 so that means Eonly+ES+GE+70=200 - you have one equation and three variables so you cannot solve the problem yet.
Statement 1 only gives you one of the variables - so that is not enough -- BCE
Statement 2 only gives you one of the variables - again not enough -- CE
If you put the equations together you have two additional varibables and can therefore solve th problem - answer is C.
Becky
Master GMAT Instructor
The Princeton Review
Irvine, CA