By applying the unified first law of thermodynamics on the apparent horizon
of FRW universe, we get the entropy relation for the apparent horizon in
quasi-topological gravity theory. Throughout the paper, the results of
considering the Hayward-Kodama and Cai-Kim temperatures are also addressed. Our
study shows that whenever, there is no energy exchange between the various
parts of cosmos, we can get an expression for the apparent horizon entropy in
quasi-topological gravity, which is in agreement with other attempts followed
different approaches. The effects of a mutual interaction between the various
parts of cosmos on the apparent horizon entropy as well as the validity of
second law of thermodynamics in quasi-topological gravity are also perused.Comment: The text has been revised and some new references are adde
