A2. Julia had eaten a box of candies in 4 days. On the first day she ate $\frac{1}{5}$ of the total number of candies. On the second day she ate half of what was left after the first day. On the third day she ate half of what was left after the second day. What portion of the candies initially contained in the box did she eat on the fourth day? Express your answer as an irreducible fraction.