A few small math problems can be added to the junior high school math problems

1. After the encounter, A arrives at B in 2 hours, and A's speed is twice that of B, and if B's speed is x, then A's speed is 2x

4*(x+2x)=84+2*(x+2x)

The solution is x=14

ab distance between two places = 4 * (14 + 2 * 14) = 168 km.

2. This question is a bit weird. 54*40%=, not an integer.

Take 22 and set the number of applicants to x

22+x)/(54+x)*100%=75%

Solution x=74

3. Is it wrong to write "one-part of the number A is equal to one-seventh of the number B"? Confirm the title again.

4. Engineering problems.

Let the desired be x: (1 x)*(4+2)+(1 10-1 x)*4+8 15=1

Solution x=30

5. Let A be x and B be y

x*20%=y*1/4

y x = 4 5 = 80% i.e. y = x * 80%, and B is 80% of A.

6. The average speed is the ratio of the total distance and time of the round trip.

2 hours 24 minutes = hours, return time = hours.

So total time = hours.

The total distance is 165*2=330 km.

Average speed = 330 km h.

7. It is also an engineering problem.

A pot (without a lid) needs 1 10 of the total material, a lid needs 1 35 of the total material, and a set needs 1 10 + 1 35 = 9 70

The number of sets that can be done = 1 (9 70) =, can only do 7 sets (note that the final answer can not be rounded to take the value, you should use the tail method, even if it is calculated to be, you can only do 7 sets).

8. It is still an engineering problem. It can be used with a speed ratio. The speed of the fast car is times that of the slow car, and when both cars are running, the distance traveled by the fast car is twice that of the slow car, that is, 3 5 of the total distance traveled by the two cars (because 3 5 is a time of 2 5, this is understood by a good understanding).

Then the total number of distances traveled by the express train = (1-3 12) * 3 5 + 1 4 * 3 5 = 1 2

The distance between stations A and B = 20 (1-1 2) = 40 km.

01) AB The distance between the two places is m kmA velocity x B y

4x+4y=m

6x=m6y+84= m

Solution 2) At the beginning, 36 women came, and x men had 36 54 + x = 1 4 solutions.

Class 3 reason, if B is right, then A, C, and D may all be right, and there is only one right, so B must be wrong.

After drinking half of it, the remaining bottle +1 2 drinks = 700 ......After drinking 1 3, there is a bottle left + 2 3 drinks = 800 ......1 6 drinks = 100

Drink = (800-700) (2 3-1 2) = 600 Bottle = 700-1 2 600 = 400

The weight difference between two drinks: 800-700 = 100 grams.

The difference in the proportion of two drinks: 1 2-1 3 = 1 6

Cola weight: 100 (1 6) = 600 grams.

Bottle weight: 700-600*1 2=700-300=400 grams.

Find the weight of the drink (800-700) (2 3-1 2) = 600

Bottle: 700-600 2=400

I don't understand it anymore.

Yes, 16 is 1, 2, 4, 8, 16, 24 is 1, 2, 3, 4, 6, 8, 12, 24

Mutual prime pairs: 8+1+1+1+1=12

Right, 858=2*3*11*13,(2*3,11*13)(2*11,3*13)(2*13,3*11).

2（1*1+2*2+..2009*2009)-2010*2010, a set of formulas to calculate the lead of the chain.

x = 7 or 14, x = 10, 24, 3, 31

Question 3 is a bit difficult for elementary school students, and you need to memorize the formula, but it will be easier if you change it to the following question:

If a b = a*a-b*b, then 1-1 3 -...Summoning....- What is the value of 2009 2010?

There are 7x in the first basket and 3x in the second basket.

3x+39）/（7x-39）=4/5

13x=351x=27

Therefore, there were 273 duck eggs in basket A and 81 duck eggs in basket B.