Student: There are 23 distinct numbers in set M, there are 28 distinct numbers in set N, and there are 12 distinct numbers that are in both sets M and N. Set H is the set containing the elements that are in at least one of sets M and N. How many elements are in set H?
Options:
(A) 39
(B) 40
(C) 51
(D) 58
(E) 63.
Another student: Let's say, hmmm...

user
{Total} = {M} + {N} - {Both}
{Total} = 23 + 28 - 12 = 39. Final answer: (A).
assistant