Track / Stage 4 / 148 of 340 #408 of 1964

Problem 408

AMC 12 late, AIME early

Combinatorics Difficulty 4.8 Multiple choice

1 Let the universal set $U=\{x \mid 1 \leqslant x \leqslant 7, x \in \mathbf{N}\}, A=\{1,2,3\}$ , if
$\complement_{U}(A \cap B)=\{1,2,4,5,6,7\},$

then the set $B$ could be:

Pick one

Official solution

(1) Since $A \cap B=\{3\}$ , choose B.

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.