MathDB
2021 Individual #20

Source:

April 28, 2022
2021 Individual

Problem Statement

In a class of seven students, a poll is conducted. The poll asks
 ~(a) Were you born after 20212021?
 ~(b) Were you born after 20192019?
 ~(c) Were you born in 20202020?
Five students respond "yes" to question (a), and four students respond "no" to question (b). If everyone truthfully answers all questions, how many students responded "yes" to (c)?
<spanclass=latexbold>(A)</span>1<spanclass=latexbold>(B)</span>2<spanclass=latexbold>(C)</span>3<spanclass=latexbold>(D)</span>4<spanclass=latexbold>(E)</span>5<span class='latex-bold'>(A) </span>1\qquad<span class='latex-bold'>(B) </span>2\qquad<span class='latex-bold'>(C) </span>3\qquad<span class='latex-bold'>(D) </span>4\qquad<span class='latex-bold'>(E) </span>5