A survey of 145 college students was done to determine their majors. Let A= the set of those majoring in art, B= the set of those majoring in biology, and C= the set of those majoring in computer science. The study revealed the following information.
n(A)=45
n(B)=55
n(C)=40
n(A?B)=12
n(A?C)=15
n(B?C)=23
n(A?B?C)=2
How many students were not majoring in any of these disciplines?