Out of total 30 students in the class, 28 know at least one of three languages, 19 speak Spanish, 11 speak French, 8 speak Chinese, 6 speak both Spanish and French, 2 speak both Spanish and Chinese, 3 speak both French and Chinese.
a) How many students know none of the three languages?
b) How many students know all three languages?
c) How many students know Spanish and French but not Chinese?
d) How many students know Chinese but neither Spanish or French?
e) How many students know Spanish but neither Chisene nor French?