###Human: 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?, ### Assistant: 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. 
 So the answer is :  10