In a math exam, the average grade of the whole class was 9 1.2. It is known that girls are 2 1, with an average score of 92 and boys with an average score of 90.5. How many boys are there in this class?

Equation solution: suppose there are x boys, then

9 1.2(X+2 1)= 92x 2 1+90.5 X

Solution: x = 24

If you don't use the equation method, do this: the total score of girls * * * is 21x (92-91.2) = 16.8, so many scores should be shared with boys, each with 0.7, so boys * * have16.8.

* * * There are 48 students, 7/ 12 of whom are boys. There are 4 1 people in this class who subscribe to the Mathematics Newspaper. So, how many boys can subscribe to the Math Newspaper at most? How many people at least?

There are 28 boys and 20 girls. If boys subscribe the most, up to 28 boys. If boys subscribe at least, all girls subscribe, and boys have at least 4 1-20 = 2 1.

Xiaoming rides a bike and Xiao Qiang walks. They came from both directions at the same time and met at the midpoint 1200m. As we all know, Xiao Qiang walks three-eighths as fast as Xiao Ming. How far is the distance between these two places?

When we met at the midpoint of the distance 1200m, Xiao Ming walked 2,400m more than Xiao Qiang, whose speed was three-eighths of that of Xiao Ming and his distance was three-eighths of that of Xiao Ming. So let Xiao Qiang's distance be 3X, then Xiaoming's distance is 8X, so 8x-3x = 2400, and the solution is x = 480m, so the total distance is 480x.

Grade 6 * * students 152 people. Eleven boys and five girls were chosen to attend the meeting, and the rest of the boys and girls were equal. How many boys and girls are there?

Suppose there are x boys, then there are (152-X) girls.

So10/11* x =152-x-5.

If x = 77, there are 75 girls.