In the spring of 20 14, the smog weather in Beijing for several days made environmental protection and health issues become the focus of attention. For the beautiful Beijing and the physical and mental health of teachers and students.

Test analysis: (1) Divide the number of students riding bicycles by the percentage to get the total number of students, and then determine the value of m. 。

(2) Calculate the number of teachers from the number of students, and then determine the number of teachers and students in private cars to complete the histogram.

(3) The method of estimating the population according to the sample.

Problem analysis: (1) According to the meaning of the question: m =12 ÷ (15 ÷ 25%) = 20%;

(2) The number of students is 60, the number of teachers is 30, and the number of teachers traveling by private car is 30-(3+9+3)= 15 (person).

The number of students taking private cars is 60-( 12+24+ 15)=9 (people).

Complete the bar chart as follows:

(3) According to the meaning of the question: 15 ÷ 25%+05 ÷ 25% ÷ 2 = 90 (person), 9+ 15=24 (person),

Then =480 (person),

A: There are 480 students and teachers traveling by private car.