Hai Josh,
I know how to answer the question, but I am too lazy to draw the Venn in computer..
Let me explain...hope it will help you..
200 - 20 (outside the circle) = 180
No one knows all three..
So, we interested to know English and German, and English and Spanish.
180 - 70 (Spanish) - 60 (English) - 0 (German) - no one knows German alone
So, you have the answer 50..we need both statement to get the answer.