Amena ate 1/2 of a sandwich, and said that her an Lavonne ate the same amount, but Lavonne argued that Amena ate more.
If Amena ate 1/2 of the sandwich, then there is only 1/2 of the sandwich left, as 1 - 1/2 = 1/2. Therefore, Lavonne couldn't have eaten more of the sandwich than Amena, because there isn't enough of the sandwich left for that.
Lavonne is incorrect.