In a class of 40 students, 12 speak both English and German. 22 speak German. If the students of the class that speak at least one of the two subjects, then how many students speak only English and not German?
You may want to rephrase the problem.
"22 speak German, of which 12 speak both languages", because
it doesn't say that the 22 German speakers speak only German.
If it were "only German" the answer would be: