2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/75569Let $n$ be a large number. A subset $A$ of $Z_n$ is complete if $S_A = Z_n$, where $S_A$ is the collection of the subset sums of $A$. Olson proved that if $n$ is a prime and $|A|> 2n^{1/2} $, then $S_A$ is complete. We show that a similar result for the case when $n$ is a composite number, using a different approach.Number TheoryCombinatorics11B75text