Answer:
At 5:59 the bin was half empty.
Explanation:
Consider the provided information.
The first minute(Starting at 12 noon), 1 person came and put in a ball. The second minute, 2 people put in one ball a piece. A minute later, 4 people put in 1 ball a piece. A minute later, 8 people put in 1 ball a piece. This pattern continues until the bin was exactly full at 6 pm.
Here we can observe that each minute the number of balls get double.
It is given that at 6 pm the bin was exactly full.
Let the number of balls at 6 pm was x.
Then the number of balls at 5:59 must be

Because the double of x/2 is x. Which is the capacity of bin.
Therefore, at 5:59 the bin was half empty or we can say that half full.