Multiple choice general knowledge math & puzzles

In a group of 15,7 have studied Latin, 8 have studied Greek, and 3 have not studied either.How many of these studied both Latin and Greek

  1. 2

  2. 3

  3. 4

  4. 5
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let L = Latin students, G = Greek students. Given: |L| = 7, |G| = 8, |neither| = 3, so |L ∪ G| = 15 - 3 = 12. By inclusion-exclusion: |L ∪ G| = |L| + |G| - |L ∩ G|. Therefore 12 = 7 + 8 - |L ∩ G|, so |L ∩ G| = 3. Option A (2) ignores that 3 people study neither subject.

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