A box contains 60 apples if one-fifth of the apples are rotten what percent of the apples are rotten

One-fifth of the apples in the box are rotten, which is equivalent to 1/5 * 60 = <<1/5*60=12>>12 apples.

To find the percentage of rotten apples, divide the number of rotten apples by the total number of apples and multiply by 100.
12 / 60 * 100 = 20.
Therefore, 20 percent of the apples are rotten. Answer: \boxed{20}.