MathDB
2022 A Individual #25

Source:

April 28, 2022
2022 A Individual

Problem Statement

For all positive integers a>1a > 1, there are divisors of 2021a2021a that are not divisors of 20212021. If there are twelve unshared divisors, including 2021a2021a, which of the following answer choices could be a possible value of aa?
<spanclass=latexbold>(A)</span>9<spanclass=latexbold>(B)</span>10<spanclass=latexbold>(C)</span>16<spanclass=latexbold>(D)</span>18<spanclass=latexbold>(E)</span>19<span class='latex-bold'>(A) </span>9\qquad<span class='latex-bold'>(B) </span>10\qquad<span class='latex-bold'>(C) </span>16\qquad<span class='latex-bold'>(D) </span>18\qquad<span class='latex-bold'>(E) </span>19