I doubt the conditions for this topic to be wrong. Many of the CSAI's BBS also had a mistake to think that this topic is wrong. The title is as follows:
According to statistical investigations, 60% of the students who participated in the examinations of the 2004 exam, 60% of the reference books A, 50% used the reference book B, 60% of the people used the reference book C. In addition, the person who uses reference book A and reference book B accounts for 30%, and people account for 30% of the reference book A and reference book C, while using reference book B and reference book C account for 40%, 10% People use the reference book A, reference book B and reference book C. Asking how many percentages have used 2 items, how many people do not use any reference book?
It is 5 years old. Most of the university has been thrown behind the school. This time before the review is not too sufficient, and the mathematics textbooks in this area are not found. However, I have done a "known gold" math question before, using the chart of the primary school students will take the picture, dealing with this type of topic is very clear, exactly the topic above.
Simplify the topic above, easy to draw, 10 people and A, b, c three options. 6 of them were selected A, 5 people selected B, 6 people selected C. Among them, there are 3 people selected by A and B, 3 people selected, and 4 people in B and C, and 1 person is also selected at the same time. Take a look at the people who choose AB, AC, and BC? How much is it not selected? The title after the change is compared to the mathematics competition questions of primary schools ^ _ ^
Let us draw a form first, 4 lines 11 columns, 10 people do not have to be divided, the list is as follows:
I doubt the conditions for this topic to be wrong. Many of the CSAI's BBS also had a mistake to think that this topic is wrong. The title is as follows:
According to statistical investigations, 60% of the students who participated in the examinations of the 2004 exam, 60% of the reference books A, 50% used the reference book B, 60% of the people used the reference book C. In addition, the person who uses reference book A and reference book B accounts for 30%, and people account for 30% of the reference book A and reference book C, while using reference book B and reference book C account for 40%, 10% People use the reference book A, reference book B and reference book C. Asking how many percentages have used 2 items, how many people do not use any reference book?
It is 5 years old. Most of the university has been thrown behind the school. This time before the review is not too sufficient, and the mathematics textbooks in this area are not found. However, I have done a "known gold" math question before, using the chart of the primary school students will take the picture, dealing with this type of topic is very clear, exactly the topic above.
Simplify the topic above, easy to draw, 10 people and A, b, c three options. 6 of them were selected A, 5 people selected B, 6 people selected C. Among them, there are 3 people selected by A and B, 3 people selected, and 4 people in B and C, and 1 person is also selected at the same time. Take a look at the people who choose AB, AC, and BC? How much is it not selected? The title after the change is compared to the mathematics competition questions of primary schools ^ _ ^
Let us draw a form first, 4 lines 11 columns, 10 people do not have to be divided, the list is as follows:
Selection | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10
------------------------------------------------ Choose A | A | a | a | a | a | a | | | |
------------------------------------------------
Select B | B | B | | | | | B | B |
------------------------------------------------
Choose C | c | | | C | C | | C | C |
------------------------------------------------
There are still 1 C without filling above, and it is satisfied with most of the topics. However, there are still 2 topics to achieve it, it is "4 people selected by 6 people and the choice of BC." I racked my brain and didn't raind the table that satisfied all the conditions, unless the title conditions were modified. Let's see if I think there is a vulnerability, because some people in the CSai system say that according to the algorithms of the aggregate, there is no error, and the two counseling books are 70%.
