Question

A poll was taken of 100 students at a commuter campus to find out how they got to campus. The results were as follows:
34 said they drove alone.
24 rode in a carpool.
28 rode public transportation.
3 used both carpools and public transportation.
3 used both a carpool and sometimes their own cars.
5 used buses as well as their own cars.
1 used all three methods.
How many used none of the above-mentioned means of transportation?

Answer 1

Number(A OR B OR C)
=NUMBER(A) + NUMBER(B) + Number(C) - Number(A AND B) - Number(A OR C) - Number(B AND C) + Number(A AND B AND C)
= 34+24+28 - 3 - 3 - 5 + 1
= 76

So 24 are not accounted for, they must have used none of the above

You could also use Venn diagrams