A watermelon stand sold 46 watermelons. Seventeen customers bought one melon, three customers bought three melons, and the rest bought two melons. How many customers bought two watermelons? Let's think first. Chain of thought:
The customers that bought one watermelon bought 1 * 17 = 17 melons. The customers that bought three melons bought 3 * 3 = 9 melons. The stand sold 46 - 17 - 9 = 20 melons to customers who bought 2 melons. Thus, 20 / 2 = 10 customers bought two watermelons.
Therefore, the answer is 10.