Final answer:
Ivy ate 2/5 of Akiko's leftover half cake, which equals 1/5 or 2/10 of the whole cake. The correct answer, 1/5 or 2/10, is not listed among the provided options.
Step-by-step explanation:
The student Akiko had 0.5 of a cake (which is the same as half a cake) left over. Her friend Ivy ate 2/5 of the leftover cake. To find out how much of the cake Ivy ate, we need to calculate 2/5 of 0.5. This can be done by multiplying the two fractions:
2/5 of 0.5 = (2/5) × (1/2) = 2/10 or 1/5
Since 1/5 is equivalent to 0.2 or 2/10 of a cake, and none of the answer choices matches this result, it seems there might be an error in the provided options. Therefore, the correct fraction of the cake that Ivy ate is 1/5 or 2/10, which is not reflected in any of the answer options given.