Difference between revisions of "2023 AMC 12A Problems/Problem 22"

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Hey the solutions will be posted after the contest, most likely around a couple weeks afterwords. We are not going to leak the questions to you, best of luck and I hope you get a good score.  
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==Problem==
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Let <math>f</math> be the unique function defined on the positive integers such that <cmath>\sum_{d\mid n}d\cdot f\left(\frac{n}{d}\right)=1</cmath> for all positive integers <math>n</math>. What is <math>f(2023)</math>?
  
-Jonathan Yu
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<math>\textbf{(A)}~-1536\qquad\textbf{(B)}~96\qquad\textbf{(C)}~108\qquad\textbf{(D)}~116\qquad\textbf{(E)}~144</math>
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==Video Solution by MOP 2024==
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https://YouTube.com/watch?v=gdhVqdRhMsQ
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==See also==
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{{AMC12 box|ab=A|year=2023|num-b=22|num-a=24}}
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[[Category:Intermediate Number Theory Problems]]
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{{MAA Notice}}

Revision as of 14:47, 9 November 2023

Problem

Let $f$ be the unique function defined on the positive integers such that \[\sum_{d\mid n}d\cdot f\left(\frac{n}{d}\right)=1\] for all positive integers $n$. What is $f(2023)$?

$\textbf{(A)}~-1536\qquad\textbf{(B)}~96\qquad\textbf{(C)}~108\qquad\textbf{(D)}~116\qquad\textbf{(E)}~144$

Video Solution by MOP 2024

https://YouTube.com/watch?v=gdhVqdRhMsQ

See also

2023 AMC 12A (ProblemsAnswer KeyResources)
Preceded by
Problem 22
Followed by
Problem 24
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 12 Problems and Solutions

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