At least two freshmen of hope primary school in 2012 were born on the same day. How many freshmen of hope primary school in 2012? There are some balls in a box. They are all the same except for different colors. Among them, there are 10 red balls, 9 blue balls and 8 yellow balls. When Liang Liang touches the ball with his eyes closed, how many balls can he touch at least to ensure that there are two balls with the same color?

At least two freshmen of hope primary school in 2012 were born on the same day. How many freshmen of hope primary school in 2012? There are some balls in a box. They are all the same except for different colors. Among them, there are 10 red balls, 9 blue balls and 8 yellow balls. When Liang Liang touches the ball with his eyes closed, how many balls can he touch at least to ensure that there are two balls with the same color?

1. 2012 is a leap year, so there are 366 days
Use the formula {the minimum number of Freshmen in 2012 (questions you ask)} = (at least number - 1) × days in 2012 + 1
The formula is as follows:
（2-1）×366+1
=1×366+1
=366+1
=367 (person)
A: there are at least 367 freshmen in this school in 2012
2. Four, three in different colors, the fourth out there will certainly be two the same

I hope that there are 450 students in the primary school, of which 3 / 4 of the girls are equal to 60% of the boys. How many boys and girls are there in this school

60% = 3 / 5, that is, 3 / 4 of girls = 3 / 5 of boys, that is, the ratio of men and women is 4:5 (4 for women, 5 for men)
450 / (4 + 5) = 50 (person)
Female: 50 * 4 = 200
Male: 50 * 5 = 250 (person)
Hope to adopt

Hope that the number of boys in primary school is 32 more than that of girls, and girls account for 48% of the total number of the school. How many students are there in this school?

100%-48%=52%
52%-48%=4%
32 / 4% = 800

The ratio of girls to boys in class 6 (1) is 2:3, and then there are four girls. At this time, the ratio of girls to the whole class is 5:11. How many girls are there in class 6 (1)?

Let the total number of the original class 6 (1) be x, & nbsp; & nbsp; 32 + 3x = (1-511) × (x + 4), & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 35x = 611 × (x + 4), & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 35x = 611x + 2411, & nbsp; 35x-611x = 2411, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 355x = 2411, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 40; 40 × 22 + 3 + 4, = 16 + 4, = 20; a: there are 20 girls in class 6 (1)