Combinatorial and particularly combinatorial NP-hard problems are of importance and interest in operations research. Therefore, the design of efficient algorithms that address these combinatorial problems are applied research lines with interesting potential. Inspired by the above, this article designs a binarization method so that continuous metaheuristics can solve combinatorial problems. The binarization method uses the concept of percentile. This percentile method is applied to the firefly algorithm. The multidimensional backpack problem (MKP) was used to verify our algorithm.