Question

How many liked folk music but not rock music?

Answer 1

Number of audience who like rock music, n(R)=114

Number of audience who like folk music,n(F)=50

Number of audience who like classical music,n(C)=41

$n(R\cap F)=14$

$n(R\cap C)=15$

$n(C\cap F)=11$

$n(R\cap F\cap C)=5$

Number of audience who like folk music but not rock music=$n\left(R\right)-n(R\cap F)$$=114-14=100$