Olympiad Mathematics, Calculation and Explanation, Olympiad Mathematics requires problem solving ide

The total amount of money for two people is certain, and after paying 10 yuan, the remaining total amount of money for two people is 1

Wang Hua pays, Li Wei doesn't spend money, his total amount of money accounts for 4 (1+4) = 4 5 of unit 1 If Li Wei pays this 10 yuan, his remaining money accounts for 1 of unit 1 (1 + this is 10 yuan after paying, and the two have a total of 25

Li Wei has 25 4 5 = 20

Wang Hua has 25+10-20=15

Wang Hua originally had x yuan, Li Wei had y yuan, y=4*(x-10)(1), x= (2).

Substitute (1) for (2) x=3 2*(4x-40-10)=6x-75 5x=75 x=15 y=20

Answer: Wang Hua originally had 15 yuan, and Li Wei had 20 yuan.

Let m=1 51+1 52++1 60 m>1 60+1 60++1 60 =1 60 100 Assuming that these 10 fractions are all 1 50, then (1 50)*10=1 5, it is obvious that s = 1 51

Set Wang Hua has x yuan.

If Wang Hua pays, Li Wei's money after payment is 4 times the amount left by Wang Hua.

Then Li Wei's money is 4 (x-10) yuan, that is, (4x-40) yuan.

If Li Wei pays, Wang Hua's money after payment is double the amount left by Li Wei.

Then it's x=[(4x-40)-10].

If the solution is x=15, then 4x-40=20

Therefore, Wang Hua originally had 15 yuan, and Li Wei had 20 yuan.

1. It is 300 kilometers from A to B. The car traveled from A to B for 5 hours, and it took only 4 hours to return, so how many percent of the speed increased when returning?

A: That's a 25% increase

2. Among the fish species raised in Huguang Village, herring accounts for 25% of the total, silver carp accounts for 20% of the herring, and silver carp accounts for less than herring in the total number of fish species?

Answer: 20% less

3 A and B each walk a certain distance, the ratio of the distance traveled is 3:5, and their time ratio is 5:4, so what is the speed ratio of A and B?

A: The speed ratio of A and B is 12:25

4. A project can be completed in 3 days by the cooperation of teams A and B. If Team A had done the project alone, it would have taken 12 days to complete. Now team A will work for 1 day, and then team B will do it alone, how many more days will I need to work?

1-1 12) (1 4) = 4 3 days.

20-2=18 (spike rolls).

10 + 15 = 25 (people).

25-18 = 7 (people).

Answer: There are 7 people who have done both questions correctly.

If the load capacity of the big car is x tons and the load capacity of the small car is y tons, then 3x = 4y can be obtained from the title

6x+10y=108②

Solve the above system of equations.

2: 6x=8y③

Substituting has: 8y+10y=108 that is, 18y=108, y=6, so x=8

Therefore, the weight of the large vehicle is 8 tons, and the weight of the small vehicle is 6 tons.

minutes) Answer: With the same speed, it takes 35 to 24 minutes to walk from the Wuming Lu Hood Building to the twelfth floor.

24 minutes: Walking from the 5th floor to the 12th floor at the same speed requires 35 (5-1)*(5 24

minutes) A; 6)

Hello: The completion time is 1 (1 10 + 1 12 + 1 15) x 2 = 8 days to help mom x days.

8/12+x/15=8/10+(8-x)/152/3+x/15=4/5+8/15-x/15x/15+x/15=4/3-2/3

2x/15=2/3

x=2/3x15/2

x=5 If you don't understand anything about this question, you can ask it, if you are satisfied, remember to adopt it, if you have other questions, please send it or click to ask me for help, it is not easy to answer the question, please understand, thank you.

Good luck with your studies!

It is equivalent to three people completing the task of transporting grain in two warehouses at the same time.

A total of 1 2 (1/10 1/12 1/15) 8 (days) Mom 8 days to transport Otokura rice.

1/12 8 2/3

Yangyang transported the rice of Yicang.

1 2/3 1/3

Yangyang helped his mother get it.

1/3 1/15 5 (days).

Dad, Mom and Yang Yang each carry a warehouse of rice 1 10, 1 12 and 1 15 every day

After setting a day to be lucky, Yangyang helped his mother to ship B day. Equation:

a/10+(a-b)/15=1 3a+2a-2b=30 5a-2b=30

a/12+b/15=1 5a+4b=606b=30

b=5 Yang Yang helped his mother transport it for 5 days.

Total = 2 (1 10 + 1 12 + 1 15) = 8 days Yang Yang Bang Dad = (1-8 10) 1 15 = 3 days to help Mom = 8-3 = 5 days.

2÷(1/10＋1/12＋1/15)

A: Yangyang helped my mother transport it for 5 days.

Let the amount of rice per warehouse be a, so the daily transportation volume of father, mother and Yangyang is 1 10a, 1 12a and 1 15a, and Yangyang helped his mother transport x days and his father for y days, and the equation was listed according to the question

1/12a（x+y）+1/15ax=1/10a（x+y）+1/15ay=a

Solving the equation yields: x=5

Yangyang helped her mother carry (5) days.

1-2÷(1/10+1/12+1/15)x1/12)÷(1/15)=(1-2÷(15/60)x1/12)÷(1/15)=(1-2x4x1/12)÷(1/15)

5 (days)2 (1 10+1 12+1 15) Calculate the time it takes to ship two barns of paddy.

Mom 5 days dad 3 days, according to the multiple of efficiency.

Set Yangyang to help my mother transport a day, a total of b days, dad transports units every day, mom transports 1 12 units per day, and Yangyang transports 1 15 units per day. Then there is (1 15)xa+(1 12)xb=1, (1 15)x(b-a)+, and the system of equations is solved. got a=5, b=8, so Yangyang helped his mother transport it for 5 days.

First of all, the question is incorrect, it should be three people buying an item together.

Let A, B, and C pay x, y, and z respectively. Therefore, the unit price of the item is x+y+zyuan(2 3)x=(1 2)y

2/3)x=(2/5)z

z-x=80

Solving the equation system obtains: x=120, y=160, z=200 The unit price of the item is 480 yuan.

Let A, B, and C pay x y z respectively

Then we get 2 3 x = 1 2 y = 2 5 z and z - x = 80

Solving the equation gives x =120

y= 160

z=200

The question is incorrect, it should be three people buying an item together. bar.

Solution, when C meets A, C and B are (40+35)*2=150, so A and C meet and use 150 (50-40)=15 (minutes), so the two places are (50+35)*15=1275 (m).