3. Let S represent the students who study
statistics, C represent the students who study calculus, and L represent the students who
study logic.
We must find n(S � C �
L). We know that
n(S � C � L) = n(S) + n(C) + n(L) - n(S � C) - n(S � L) - n(C � L) + n(S � C � L).
Now substitute the information given in the problem into the above equation to find n(S � C � L).