d***u
发帖数: 19 | 1 You have nine balls, three of which are slightly heavier, and three of
which are slightly lighter than the normal three. All three balls in each
group have the same weight. All nine balls are identical otherwise. Your
mission is to determine the group of every ball using a pair of scales.
How many weighings are needed in order to ensure the accomplishment of
your mission?
Notes:
1. The difference of weight between the heavy and normal balls is not
necessarily equal to the difference of weight between the light and normal
balls.
2. The scales show only which side is heavier; it does not show the
difference of weight. | p******i
发帖数: 1358 | | d***u
发帖数: 19 | 3 咋得出的2次？
还在琢磨7次可不可以完成:(
【在 p******i 的大作中提到】
: 2次
: 为啥要3个球？
|
|
