Kummoon and Changphas in Quasigroups and Related Systems 25(2017), 87 94 state the following question: "Is it true that for any two bi-bases of a semigroup have the same cardinality?" In this paper, we provide a semigroup of order n for every n 5 which has two bi-bases with diferfent cardinalities that is shown the answer of question is negative.
