How to improve the relationship between the number of civil servants in the examination?

You can remember some commonly used formulas:

First, the itinerary:

A simple encounter/pursuit:

Xiaoli, Xiaomei and Fan Xiao decided to drive from S City to L City. Fan xiaoxian begins. If Xiaomei leaves 10 minutes later than Fan Xiao, Xiaomei will catch up with Fan Xiao 40 minutes after departure. If Xiaoli leaves 20 minutes later than Xiaomei, Xiaoli will catch up with Fan Xiao at 1 hour 30 minutes after her departure. Assuming that the distance between S city and L city is far enough, all three people are driving at a constant speed, and Xiaoli catches up with Xiaomei () hours after her departure.

A.2 B.3 C.4 D.5

According to the stem information, we will find that the word with high frequency is "catch up", so this problem can be decomposed into three catch-up problems and solved repeatedly by using the catch-up distance formula.

1, Xiaomei Chasing and Fan Xiao: Chasing distance = 10 minute Fan Xiaoxian's travel distance.

2. Xiaoli catches up with Fan Xiao: catching distance = Fan Xiao walks 30 minutes earlier than Xiaoli.

3. Xiaoli catches up with Xiaomei: catching up distance = Xiaomei walks 20 minutes earlier than Xiaoli.

You can calculate t=300 minutes, that is, 5 hours by solving, and choose D.

Second, the question of tolerance:

(1) Their inclusion relation:

For example, there are 200 students in a class. Now, let's investigate your satisfaction with the three teachers who teach English, mathematics and English. 100 people are satisfied with the Chinese teacher, 80 with the math teacher and 70 with the English teacher. There are 30 people who are satisfied with both Chinese and math teachers, 20 people who are satisfied with both Chinese and English teachers, 10 people who are satisfied with both math and English teachers, and 5 people who are satisfied with all three teachers. How many people are dissatisfied with the three teachers?

A. 1 B.5 C.6 D. 10

When answering the tolerance question, you should read the question carefully and choose the corresponding formula according to the known conditions of the question and answer it. According to the meaning of the question, there are 200 complete works, among which

Third, the calculation problem

1, arithmetic progression:

2. Geometric series:

For example, in a math exam, after the teacher sorted the grades of the whole class, it was found that 65,438+065,438+0 students had the same grades, and the grades of 65,438+065,438+0 students with the same grades were just the middle item of arithmetic progression. The first student got 99 points, and the last student got 3 1 point. Given a class total score of 20 15, how many people are there in the class?

A.25 B.27 C.29 D.3 1

First of all, we should translate the text information into mathematical language. According to the meaning of the question, find n? According to the known conditions given in the title, we first solve it according to the properties of arithmetic progression. According to the option, n is odd, so. Therefore, according to the summation formula, the solution is n=3 1. Option d

The above is a common formula about the quantitative relationship in the process of preparing for the exam summarized by Chinese public education experts. Formulas in mathematics are not rote learning, but should be used flexibly on the basis of understanding, so everyone should continue to work hard and do more problems to improve the speed and accuracy of doing problems.