Total amount of students: 102.
47 study french, where 23 study only french.
46 study german, where 20 study only german.
43 study spanish, where 16 study only spanish.
15 study both french and german.
a) How many study all 3 languages?
b) How many study neither of the languages?
c) How many study both french and spanish?
I have tried really hard using a venn-diagram to get the answers but failed, if someone could explain how you reach the answer and not just the answers it would be very very appreciated since I need to comprehend the procedure for future calculation. Once again, thanks in advance.