iran-konkur 2013 Q152

iran-konkur · Other · konkur-riazi_1392 Number Theory Modular Arithmetic Computation
152. For how many natural numbers less than $50$, is $7^n + 42$ divisible by $43$?
(1) $8$ (2) $7$ (3) $8$ (4) $9$
\textbf{152.} For how many natural numbers less than $50$, is $7^n + 42$ divisible by $43$?

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(1) $8$ \hfill (2) $7$ \hfill (3) $8$ \hfill (4) $9$

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