Riddle: A box of hardware contains nuts and bolts. The bolts account for 25 percent of the number of items in the box. What percentage are the bolts of the entire box?
Answer: 20 percent. For example, there are 10 bolts. Since the number of bolts is 25 percent of the number of items, there must be 40 nuts. The total number of items = 10 bolts + 40 nuts = 50. So, 10/50 = 1/5 = 20%.