Competition problem — Combinatorics

Library / /83 of 520

Combinatorics Difficulty 5.1 AIME, harder Find the answer

99. Xiao Ding said: "March 13 is a Friday." Xiao Qiao said: "March 11 is a Sunday." Xiao Pang said: "What Xiao Ding and Xiao Qiao said is incorrect." Xiao Ya said: "March 12 is not a Saturday." If only one of the four is correct, then March 12 is a $\qquad$ _.

Your answer

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Solution

answer: six

Want a route through all this instead of an archive? The track puts 2,000 problems in a working order, from AMC 10 level to the IMO shortlist.

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