Hello!

I can understand why the answer is 121, if we were to not consider the “In the graduating class…” portion of the problem, but when I read that part of the problem, I thought they meant all 236 graduating students took only algebra, only chemistry, or both. Is my logic wrong?

Thanks so much in advance

See the question doesn’t mentioned the word only (Sadist ETS people ) .

So what you’re looking at is : Group Chemistry + Group Algebra - Both + Neither = 236(Total)

Substituting values for Chemistry and Algebra :

142 + 121 - Both + Neither = 236

Both - Neither = 27.

Taking extreme cases :

Case 1 : minimum → We need to have a very slight overlap, thus make Neither = 0. So, Both equals 27.

Case 2 : maximum → Put all chemistry student under Algebra . So both turn out to be 121 → Ans

Haha “sadist ETS people”

Thank you for the thorough explanation!