1/5 secondary
Solutions; It will take another x hours to finish.
( 1/7.5+ 1/5)* 1+ 1/7.5x = 1
1/3 * 1+2/ 15x = 1
1/3+2/ 15x= 1
2/ 15x=2/3
x=5
1+5=6 (hours)
Answer; * * * It takes 6 hours to complete.
Answer;
In the seventh grade, the first volume of the People's Education Edition mathematics textbook p66 turns to 7 1 page. 4. Solution: Suppose the population of another village is XX (2x-3) = 834x2x-3 = 8343x = 837x = 279. Larger villages: 934-279=555 (people). 5. Solution: Suppose it took B x time10 (x =15x10x300 =15x10x-15x =-300-5x =-300. 2 (5x20) = 2981/2x5/2x10 = 2983x10 = 2983x = 288x = 96 The speed of the maglev train is: 96 times 5 20=5007: Solution: Let the windless wind speed be x, Then the downwind speed is (x2), the headwind speed is (x-24)2 hours and 50 minutes = 17/6 hours 654336x=- 140x=840, and the voyage is 3x (840-24) = 3x816 = 2448 (. 9. Solution: Suppose X people do it for 2 hours, and 2/80X 8/80(X 5)=3/4 (since this problem, I won't write the process. Then buy black cloth (138-X) and Russian ruler 3X 5( 138-8)=540 to get 75.63 (two oh) 12 solution: suppose that B has x sheep and A has only x 21= 2 (x I'll call one by one) 13. Solution: suppose that the sales volume increases by x compared with the original price. It takes a long explanation to get 0.9 (1x) =1/9ke = 0.11increase1.1/solution: 2 = 36 = 36/2 (I copied the question 15). I'm so tired. Wow, I also said a lot. ==b The math answer to this question in grade seven is very difficult. I've tried to answer it. Give me a satisfactory answer: henanlj. /
The first volume of seventh grade mathematics 102, pages 7 and 8 10, 1 1 problem equation and answer 7.
Solution: Assuming that the speed of the plane is X kilometers per hour when there is no wind, it is obtained.
(X+24) times (5 divided by 6)=3(X-24)
The solution is X=840.
(840-24) times 3 = 2448km.
A: When there is no wind, the speed of the plane is 840 kilometers per hour.
There are 2448 kilometers between the two cities.
There are 4 questions and 5 questions on page 47 of the first volume of the seventh grade mathematics textbook published by People's Education Press, and only the fourth question is required. Use scientific counting methods to represent the following numbers.
235000000 188520000 70 1000000000 -38000000
5. What is the original number of the following numbers expressed by scientific notation?
3× 10∧7 , 1.3× 10∧3 , 8.05× 10∧5 , - 1.96× 10∧4
The seventh grade mathematics textbook (Zhejiang Education Edition) Volume 1 This friend, do you want to ask for a mathematics textbook, or do you have other questions? Can't you answer until you make it clear?
P7 1, 2 and 3 in the seventh grade mathematics textbook published by People's Education Press. It is urgent. Please kneel down and thank 8X- 1 5 5 1.
-3 ( - )=- - = - 2 -
6 2 2
-x+2x-2-3x-5=-2x-7
The seventh question on page 7 1 of the seventh grade mathematics textbook is 1:3, which means that the opponent won one game, and the other side won (lost) three games, but actually lost two games, -2.
At 3:2, I won three games, and the other side won (lost) two games, but actually won one game,+1.
0:3, I didn't win a game, the other side won (lost) three games, and actually lost three games, -3
3: 1, I won three games, and the other side won (lost) one game, but actually won two games, +2.
Total net wins =-2+ 1-3+2=-2, which means two losses.
The contents of questions 4 and 5 on page 106 of the seventh grade people's education edition mathematics textbook are in urgent need. A middle school student transforms the playground by himself, and it takes 7.5h hours for a seventh-grade student to do it alone. If the eighth grade students are asked to work alone, it will take five hours to finish. How long will it take if grade seven and grade eight students do 1h together, and then grade eight students finish the rest separately?
It takes 80 hours for a person to sort out a batch of data. Now it is planned that some people will do it for 2 hours first, and then 5 people will do it for 8 hours to finish 3/4 of the work. How to arrange the specific number of people involved in sorting out the data?
First of all, my math book is published by PEP. See if the progress is the same as yours.
You are really careless.
The latest People's Education Edition, the first volume of the seventh grade mathematics textbook, 97 questions (screenshots), I will tell you if there is any reward.
In the second question on page 1 19 of the seventh grade mathematics textbook, a car goes back and forth between Party A and Party B, which are 70km apart. Because there is a hill with uniform slope in the distance, it takes 2.5 hours to go there and 2.3 hours to return to use. It is known that cars travel 30km per hour on the flat ground, 40km per hour when going downhill, and 20km per hour when going uphill, so the distance between uphill, downhill and flat ground can be calculated.
Solution: One kilometer uphill, and 70-a-b kilometers downhill.
a/20+b/40+(70-a-b)/30 = 2.5( 1)
a/40+b/20+(70-a-b)/30=2.3(2)
( 1)-(2)
a/40-b/40=0.2
a-b=8
A=b+8 substitution (1)
solve
B=4 kilometers
A =12km
So to go there, it is 70-4- 12 = 54km, and uphill 12km. 4 km downhill
involve