Math masters, hurry up and come in! Hurry!

1.60*2+96*1=216 km (the difference between the distance traveled at two speeds in a specified time).

210 (96-60) = 6 hours The prescribed time is 6 hours.

60*(6+2)=480 km (distance).

480 6 = 80 km (speed required).

2.28 14 = 2 (the number of boys is twice as large as that of girls, i.e. (the difference between the average score of boys and the average score of the class is 1 2 of the difference between the average score of girls and the average score of the class).

4 2 = 2 points (the average score of boys is 2 points less than the average score of the class) 84 + 2 = 86 points (the average score of the class).

86 + 4 = 90 points (average score for girls).

1. Are you so anxious that you forgot the topic?

Set the punctuality time t hours, speed v

Then vt=96 (t-1).

vt=60×（t+2）

96t-96=60t+120

36t=216

t = 6v = 96 5 6 = 80 km h.

2. It seems that there is a lack of conditions!! Give it a try!!

Assume that the number of boys n, the average mathematics score of girls is m

Then the average score of the class is (84n+14m) (14+n)m-(84n+14m) (14+n)=4

14m+mn-84n-14m=56+4n

mn-88n=56

n（m-88）=56

Apparently 100 m 88

i.e. 12 m-88 0

So M-88 could be equal to or 8

The corresponding n is equal to or 7

But there are only 7 boys in a class, a total of 14 + 7 = 21 students, which is unreasonable.

So, there should be 28 or 14 boys, and the girls' score is equal to 88 + 2 = 90 or 88 + 4 = 92.

There is indeed a lack of conditions to determine the exact number of boys].

Suppose it takes t hours to arrive on time and the speed is v kilometers.

96*(t-1)=60*(t+2) gives t=6

60*(t+2)=vt, v=80

1.Let the total length be x meters, x 96 + 1 = x 60-2, solve x = 480 km, and reach the punctuality as 480 60-2 = 6 hours.

2.Let the average score of female students be x, (14x+28*84) (28+14)=x-4, and solve x=90 points.

The overlapping area of two rectangles is equivalent to one-seventh of the area of the large rectangle and one-fifth of the area of the small rectangle, which is 7 parts for the large rectangle and 5 parts for the small rectangle.

The shadow of the chaotic limb surface is 6 parts of the large rectangle + 4 parts of the small rectangle, and the area of the shadow part is 200 square centimeters, each copy: 200 (6 + 4) = 20 (square centimeters).

The area of the overlapping part is 20 square centimeters.

The stool replied

The area of the shaded part on the left is 1 1 7 1 6 times that of the overlapping part, the area of the shaded part on the right is 1 1 5 1 4 times the area of the overlapping part, and the area of the shaded part is 6 4 10 times the area of the overlapping part.

The area of the overlapping part is 200 10 20 square centimeters of thick acacia wood.

Regard the whole figure as a ruined Zheng whole shirt mill, and the shadow part as 1 part, this or Yu Dou whole should have such 7 + 5-1 = 11 parts, of which the shadow part accounts for 11-1 = 10 parts, so the area of the overlapping part is 200 10 = 20 square centimeters.

Let the area of the overlapping part be x, then the area of the large rectangle is 7x, the area of the small rectangle is 5x, the area of the shaded part plus the area of the overlapping part multiplied by 2=7x+5x, that is, 200+2x=7x+5x

Get x=20

The overlapping part is called the area of 20 square and the pin balance centimeter.

You can check out the math network.

The quickest and most effective way:

One is to read textbooks, understand concepts, theorems, and formulas first, and understand these things.

Second, I still read the textbook, see how the example problems in the books are solved, and learn the direction of solving the example problems. That is to say, when you encounter the same problem, how should you think about the direction of solving the problem, that is, which direction to learn to go in order to reach the goal. This is the most important thing to learn.

This is fundamental to learning mathematics. Learn to understand the direction of the problem, that is, you have wisdom, learn the concept, just learn the knowledge, wisdom is the most important.

Third, we still have to do some questions, but they are not question sea tactics. I have to learn to summarize, that is, which direction I should consider when I encounter this kind of topic. What conditions are given to this question, and which formula do you want to use?

In general, conditions must be used up, but they will not be insufficient, this is a principle. Just do the questions and learn these things, I wish you good results.

If you want to use these "Test Question Research" and "Golden Exam Papers", I personally recommend "Golden Exam Papers".

21*6=126pcs.

140-126=14.

14 2 = 7.

21-7=14.

1*14=14 pairs.

24-14 = 10 pairs.

10 1=10.

14-10 = 4 pcs.

7 spiders, 10 dragonflies, 4 cicadas.

Why can't it be changed?