GMAT 数学题（15）

sdcar2010 · 发表于 2011-2-12 23:00:32

At Beijing 101 Middle School, among the senior class, 35 seniors play soccer, 37 seniors play football and 28 seniors play basketball. Of these senior students who play these three sports, 14 play both soccer and football, 19 play both basketball and football and 12 play both soccer and basketball. What is the smallest possible number of seniors who play all three sports? And why?

adazhanglin · 发表于 2011-2-12 23:50:54

仅是我自己的想法。
首先画一个图，三个圆圈交在一起。三个圆中间重叠的部分就是X所求。
两个圆重叠的部分减去X分别是19-x，14-x，12-x。剩下的只玩BAS,SOC,FOT的就是x-3，14-x，11+x。根据人数大于0原则，应该是3<=x<=12，所以最小应取3.

sdcar2010 · 发表于 2011-2-13 03:36:40

LS is right! Good job.

GMAT 数学题（15）

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