Olympiad cooperation issues to process .

The two floors above are really nonsense, won't you say anything? Wasted sofa ......To get back to the point, first of all, I asked the landlord a good question, and I was fortunate to have a question from the landlord! - Title:

Engineering team A has 1 day off for every 5 days of work, engineering team B has 2 days off for every 4 days of work, and it takes 47 days for team A to do a project alone, and 58 days for team B to do it alone. If two teams work together, how many days can it be completed?

Ideas: 1 5 6

5 6 = 5 6 The number of days A works is 5 6

4 6 = 4 6 The number of days B worked is 4 6 of the total number of days, and this problem becomes a fraction problem.

58-47=11 B is a few days slower than A.

5 6-4 6=1 6 B is a fraction slower than A.

11 1 6 Divide the known number by the corresponding fraction to get the unit "1".

Efficacy: 1 116 3 = 3 116

Complete! Alas.. My fingers hurt, I can't help it, who wants him to be the landlord's problem

I can do it, but the process is difficult to write. It's long, it's long.

After the elder brother chased the younger brother, the younger brother walked a total of 6,000 meters, because the elder brother chased the younger brother and returned at the same speed and arrived at the destination at the same time as the younger brother, so when the elder brother chased the younger brother, the younger brother walked exactly half of the remaining 6,000 meters, that is, he had already walked 4,000 meters, and there were still 3,000 meters to reach Town B. Therefore, the elder brother walked a total of 8,000 meters in 2 hours, and the younger brother walked 6,000 meters in 2 hours, so the younger brother walked 3,000 meters per hour.

Catch-up time 1 (4-x).

During this time, the elder brother walks 4x 1 (4-x) and the younger brother has to walk 7-4x 1 (4-x) The elder brother returns to A and the younger brother goes to B for the same time.

4x 1/(4-x)】÷4 = 【 7-4x 1/(4-x)】÷x

I don't even know if it's right.

7. Set Grandpa X, Dad Y.

First sentence: x-y=y-12

Second sentence: x-y = 84-x

Solve: x=60, y=36

8, you can understand that Xiaohong bought two copies from Xiao Ming's hand with yuan's **.

9. Let the middle digit of five odd numbers be x, then (x-4)*(x-2)*x*(x+2)*(x+4)=45045

10. Let the total wood be 1, a table with material X, and a chair with material Y, which can be made into n sets;

x=1/20

y=1/30

n*(x+y)=1 The solution gives n=12 sets.

12, let two prime numbers one x and one y, then 3x+2y=200

2(x+y)=200-x

The left side of the equation is an even number, and on the right side is an even number only if x is 2, 200-x is even (only 2 is even for prime numbers).

13, the overlapping part is m, then A = 13*6-m

B = 7*5-m then A minus B is 13 * 6-7 * 5 = 43

14, set a total of x;

The first one takes x 2 + 1 2, and the remaining x 2-1 2;

The second one takes (x 2-1 2) 2+1 2, and the remaining x 2-1 2-[(x 2-1 2) 2+1 2];

The third one takes 2+1 2 and leaves 1 left.

So the sum of all that is taken and what is left is the original total, i.e.: x 2+1 2+(x 2-1 2) 2+1 2+ 2+1 2+1=x

Solve x = and you're done.

15, it's 4 copies!

If the least one part is x, then the other three parts are x+2, x+4, x+6;

then the total x+x+2+x+4+x+6=48

x=9 so the minimum is 9 and the maximum is 15, and the other two are 11 and 13.

(7) Let the grandfather be x years old now and the father be y years old.

x-y=y-12

x-y=84-x

x=60 y=36

So my grandfather is 60 years old and my father is 36 years old.

8) 2 people should take the same amount of money homework books for the same bibliography should be 10 books, so Xiaohong takes 2 more books for yuan, and one is yuan.

So the five numbers are 5, 7, 9, 11, 13

10) A desk needs 1 20 of wood and a chair needs 1 30

So if you do it as a set, you should be able to do 1 (1 20 + 1 30) = 12 sets.

11) 168*14 28+168=252 pieces.

12) 2 times the last prime is an even number, because the sum is 200, so 3 times the previous prime number is also an even number, so this prime number is an even number, and only 2 in the prime number is an even number, so the previous prime number is 2, and the last one is 97, and the sum of 2 numbers is 99

13) S A - S B = (S A + S overlap) - (S B + S overlap) = S parallelogram - S rectangle = 13 * 6-7 * 5 = 43

14) Push backwards: After the third monkey takes half of it, there is still one, so there are 3+ after the second monkey takes half of it, so before the second monkey takes it, there are 7+ after the first monkey takes half of it, so there is one before the first monkey takes it, that is, the original 15 peaches.

15) Set at least one copy as x, and the other parts as x+2 x+4 x+6

x+x+2+x+4+x+6=48

x=9, so the minimum portion is 9 pieces, and the maximum portion is 9 + 6 = 15 pieces.

7. If the difference between the father and the grandfather is x years, then the father's age is (12+x) years old, and the grandfather's age is (12+2x) years. By the title:

84=(12+2x)+x x=24 Father is 36 years old and grandfather is 60 years old.

8. With the same amount of money, a total of 8+12 copies were bought, so each person's money can buy 10 copies.

Xiao Ming took 8 copies and got back the yuan, then the unit price = yuan.

45*1001=(5*9)*(7*11*13) consecutive odd numbers are

10. Wood for each table 1 20, wood for each chair 1 30 sets = 1 (1 20 + 1 30) = 12

11. Notice that 14m is half of 28m, so the bricks used are also half of the original, that is, 84.

Total number of bricks used = 168 + 84 = 252 pieces.

12. 2 times of prime number a is an even number, prime number a 2 times + prime number b3 times = 200, then prime number b 3 times must also be even, that is, prime number b is an even number.

Only 2 of prime numbers is even, so if prime number b is 2, then prime number a is 97 and is 99

13. There is a problem with the topic, and it is not clear how it overlaps;

14. Push backwards. After the second monkey takes it, there is still a number of = (1 + after the first monkey takes it, there is still a number of = (3+

Before the 1st monkey is taken, the total number = (7+

15. Let the least one have x blocks, then.

x+(x+2)+(x+4)+(x+6)=48x=9, up to one copy=x+6=15

7. y-x=x-12,y-x=84-yy=60,x=368.Yuan.

10.12 sets.

11.252 blocks.

12.The sum of two prime numbers is 99

13.43 square centimeters.

14.15 pcs.

15.The least one has 9 pieces, and the most one has 15 pieces.

Solution: Eat on the third day: 1 piece.

Eat the next day: 2 pcs.

Eat on the first day: 4 pcs.

Mom bought a total of 4 + 2 + 1 = 7 pcs.

1 12 is walking speed + elevator speed;

1 24 is the walking speed - the elevator speed.

Let Xiao Ming's speed x elevator speed y distance be 1

12x+12y=24x-24y

3y=x to either side of the above.

36y+12y=1 on the left

y=1/48

So it takes 48 seconds.

Let the height of the building be s, and the speed of the elevator and Xiao Ming will be v and u respectively

then there is s=12(v+u).

s=24(u-v)

The solution is v=s 48

So it takes 48 seconds.

Let the distance be 1Among them, Xiao Ming's speed is v1, and the speed of the escalator is v2, then the equation group can be obtained

v1+v2=1/12………1）

v1-v2=1/24………2）；

1) - (2) formula can be obtained: 2v2 = 1 12-1 24 = 1 24, then v2 = 1 48, so Xiao Ming only stands on the elevator and does not move to the upper floor for 48 seconds.

The correct answer should be 48 seconds, and the calculation of 16 seconds is: If Xiao Ming walks upstairs in 24 seconds against the elevator, it should be 16 seconds, and the error point here should be upstairs and downstairs, that is, who is faster and who is slower between the elevator and Xiao Ming.

Xiao Zhang and Xiao Li's 1-hour journey is equal to the whole journey.

1 hour 40 minutes = 5 3 hours.

So when Xiao Li caught up with Xiao Zhang, the two of them had a total of 5 3 full journeys, and Xiao Li had 1 full journey more than Xiao Zhang.

Xiao Li walked (5 3 + 1) 2 = 4 3 whole journeys.

The whole journey is 5 3 15 4 3 = km.

The two met again and traveled 3 full journeys in 3 hours.

Xiao Li lined: 15 3 = 45 km.

After Xiao Li arrived at place B, he traveled again: a kilometer.

Let the velocity v of the small sheet, and the distance between the two places is s

15 + v = s 1)(15 - v )*1 + 40 60) = s i.e. 75 - 5v = 3s 2)(1) 3 (2).

30 + 8v = 0

v = 30 / 8 =

s = time t for re-encounter

Then (15 + v) t = 3s

t = 3 (hours).

At this time, the distance traveled by Xiao Zhang =

Away from B - =

That is, Xiao Li walked km again

Let's draw a line, let Xiao Li and Xiao Zhang meet at point A, Xiao Li and Xiao Wang meet at point B, and when Xiao Li meets Xiao Wang, Xiao Zhang (take 6 minutes) to walk to point C.

ac is the distance that Xiao Zhang took 6 minutes to walk after meeting Xiao Li: 1 10 hours * Xiao Zhang's speed 5km hour =

ab is the distance that Xiao Li walked in 6 minutes after meeting Xiao Zhang: 1 10 hours * Xiao Li's speed 10km hour = 1km

BC means that after they set off at the same time, the distance caused by the speed difference between Zhang and Xiao Wang = to generate this distance, it takes a total of hours=hours.

This time is the total time that each of them has gone.

Then, the whole journey from A to point B is the whole journey of Xiao Wang: hour * 4km hour = 6km B to point B is the whole journey of Xiao Li: hour * 10km hour = 15km A and B are 21km

Xiao Li walked to the end: 21km 10km hours = hours, that is, the answer on the second floor is 126 minutes.

The speed of A: v1 The speed of B is not coarse v2

Solution: Dry Pants Town v1 v2=

The speed of A is twice that of B pure group.