题目:of the 200 students at college T majoring in one or more of the sciences, 130 are majoring in chemistry and 150 majoring in biology. If at least 30 of the students are not majoring in either chemistry or biology, then the number students majoring in both biology and chemistry could be any number from
a) 20 to 50
b) 40 to 70
c) 50 to 130
d) 110 to 130
e) 110 to 150
问题:这道题能理解到是用集合的知识点,但是无论怎么做都无法突破,得到最后结果。还请老师讲解。谢谢
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sysadmin老师
提问:
调查1200人对A B C 的喜好,喜欢A的40%,喜欢B的58%,喜欢C的40%,同时喜欢AB的30%,求喜欢C但不喜欢A B的人