There are 3 tennis balls in a barrel, and 12 barrels can be contained in a box. If the price of tennis balls per barrel is 2 yuan. So how much does a box of tennis balls cost? To answer this question, what information is useless? How many balls are in a bucket
一桶网球为3个，1箱可装12桶，如果每桶网球价格为2元．那么一箱网球要多少钱？解答这一题，哪些信息是没用的？一桶有多少个球
<result>3</result>