(2)(5y+ 1)+( 1-y)=(9y+ 1)+( 1-3y)；
(3)[()-4]= x+2；
20%+( 1-20%)(320-x)= 320×40%
2(x-2)+2=x+ 1
2(x-2)-3(4x- 1)= 9( 1-x)
1 1x+64-2x = 100-9x
15-(8-5x)=7x+(4-3x)
3(x-7)-2[9-4(2-x)]=22
3/2[2/3( 1/4x- 1)-2]-x = 2
1 2x- 10.3x= 15
2 0.52x-( 1-0.52)x=80
3 x/2+3x/2=7
4 3x+7=32-2x
5 3x+5( 138-x)=540
6 3x-7(x- 1)=3-2(x+3)
7 18x+3x-3 = 18-2(2x- 1)
8 3(20-y)=6y-4(y- 1 1)
9 -(x/4- 1)=5
10 3[4(5y- 1)-8]=6
10/3 (x/5+3/7)=9x/2
5/3(x+0.5)+2=3x-6
5x+2(2x/3+2)=2/3(x-6)+2
(2×7)/2-(6×5)/3 = 2×3
(3x+2)/5-(x-6)=x/3
6x-(x/3+2)=2(x/5+5/2)-3
3(x/ 1 1-2)-5=2+3x/3
10/3(2×6)= 3/5
x/2-(x/3-2)=3
2/3(x+3)-3=5x/3
5/3(2x-5/3)=2x/5-8/9
25(x/3-x/2+2/5)-2 = 3/5(x-2/7)+4/9
You can also make your own, and the structure is similar:
Score * (score *X+ score) = score (score *X+ score)
A train passes a 300-meter-long iron bridge. It takes 30 seconds to pass completely and 10 seconds to stay completely on the bridge. The length and speed of the train.
Solution:
l+300=30v
300-l= 10v
v= 15m/s
L =150m
Answer: vehicle length150m, speed15m/s. ..
2. A class of students went to Beishan for an outing, 18km. There is only one car, so it needs to be divided into two groups. Group A takes the bus first, and Group B walks. The bus goes to Group A, Group A gets off and walks, and the bus goes back to Group B. Finally, the two groups arrive at Beishan at the same time. Given the car speed of 60km/h and the walking speed of 4 km/h, find the distance from point A to Beishan.
Let the speed of a be x and the speed of b be y.
80x+80y=400
80y-80x=400
So x=0 y=5 (the time of this question is 80 seconds, which is not true)
3. Let the distance from point A to Beishan be X, and when the car returns to group B, the distance from point B to the starting point is Y..
Then [x-4 * (18-x-y)/60]/4 = (18-y)/60.
y/4 =( 18-x)/60+( 18-x-y)/60
So x=2 y=2.
Point A is 2 kilometers away from Beishan.
3. Peony Cup football match 1 1 round (that is, each team needs to play 1 1 game). If you win a game, you will get 3 points, if you draw a game, you will get 1 point, and if you lose a game, you will get 0 point. The team of Guoxing Sangao Club won four times as much as it lost, and the result was * * * 25 points. The team won the trophy.
Let x win and y lose, then 1 1-x-y will be even.
x=4y
3x+ 1 1-x-y=25
x=8
y=2
Eight wins and two losses 1 draw.
In extracurricular activities, some students take part in group activities. Originally, there were 8 people in each group, and then they were regrouped, with 12 people in each group, which decreased by 2 groups. How many students are there?
Suppose there is an X organization. So the number of people is 8x.
(x-2) 12=8x
x=6
* * * There are 48 people.
5. There is a high-speed wind belt above the surface 10 km. Suppose there are two planes flying at the same speed in this wind belt, and one of them flies from A to B, with a distance of 4,000m, which takes 6.5h; At the same time, another plane flew from B to A in only 5.2 hours. What is the average speed of the plane and the wind?
Let the average speed of the aircraft be xkm/h and the wind speed be ykm/h.
From the meaning of the question, we can see that there is headwind from A to B and tailwind from B to A, and the countable equation is:
x+y=4/5.2
x-y=4/6.5
Solution: x = 9/ 13, y =113.
6. A team travels at a speed of 5 kilometers per hour. Twenty minutes later, a correspondent caught up with the team at a speed of 15 km/h. How many hours will it take him to catch up with the team?
5*( 1/3)+5*X= 15*X
x= 1/6
6. A harvester harvests 12 hectares of wheat every day. Cutting 2/3 of the wheat field improved the efficiency by 5/4 times, so it was completed 1 day ahead of schedule. How many hectares of wheat fields are there?
The wheat field is x hectares, because two thirds of it has been cut.
A company borrowed 400,000 yuan from a bank to produce new products. It is known that the annual interest rate of this product is 15% (excluding compound interest, that is, interest is not recorded every year before the loan). The cost of each new product is 2.3 yuan, and the price is 4 yuan. Taxable amount is 65,438+00% of sales. If this product produces 20 pieces a year, calculate the profit (profit = sales volume).
If the length-width ratio of two rectangles is 2: 1, the width of the big rectangle is 3 cm more than that of the small rectangle, and the circumference of the big rectangle is twice that of the small rectangle, find the areas of these two rectangles.
Fill a song with water in a cylinder with a diameter of 5 cm and a height of 18 cm, then pour the water in the bottle into a cylindrical plum with a diameter of 6 cm and a height of 10 cm. Can you pack it all? If not, how high is the water level in the bottle? If it can be filled, find the distance from the water surface to the mouth of the cup! ! !
1. solution: we assume that it will be paid off after x years.
Then the amount to be repaid by * * * is 400,000 yuan (1+0. 15x).
Over the years, * * * has produced a 20x product, consumption cost 2.3 * 20x, and sold it to get 4* 20x.
The tax is 0. 1*4* 20x.
So the profit is 4* 20x-2.3 * 20x-0. 1*4* 20x.
So the equation is 4 * 20x-2.3 * 20x-0.1* 4 * 20x = 400000 (1+0.15x).
The solution is x= negative!
So, please check the unit in the title. The estimated cost price and selling price are wrong.
On such a topic, one year's sales are not enough to pay interest.
2. Solution:
Let a large rectangle be x in length and 0.5x in width.
The width of the small rectangle is 0.5x-3 and the length is 2(0.5x-3).
The equation is as follows
2( x+0.5x )=2*2( 0.5x-3 + 2(0.5x-3))
The solution is x= 12.
It is easy to find that the areas of the two rectangles are 72, 18 respectively.
3. solution: let the distance from the water surface to the cup mouth be x,
The volume of water is 3.14 * 2.5 * 2.5 *18 = 353.25 cubic centimeters.
Equation based on new container volume
353.25+3. 14 * 3 * 3 * x = 3. 14 * 3 * 3 * 10
The solution is x =-2.5cm.
A negative value indicates that water will overflow.
The volume of spilled water is 3. 14*3*3*2.5=70.65.
The height in the original container is 70.65/3.14/2.5/2.5 = 3.6 cm.
A train passes a 300-meter-long iron bridge. It takes 30 seconds to pass completely and 10 seconds to stay completely on the bridge. The length and speed of the train.
Solution:
l+300=30v
300-l= 10v
v= 15m/s
L =150m
Answer: vehicle length150m, speed15m/s. ..
2. A class of students went to Beishan for an outing, 18km. There is only one car, so it needs to be divided into two groups. Group A takes the bus first, and Group B walks. The bus goes to Group A, Group A gets off and walks, and the bus goes back to Group B. Finally, the two groups arrive at Beishan at the same time. Given the car speed of 60km/h and the walking speed of 4 km/h, find the distance from point A to Beishan.
Let the speed of a be x and the speed of b be y.
80x+80y=400
80y-80x=400
So x=0 y=5 (the time of this question is 80 seconds, which is not true)
3. Let the distance from point A to Beishan be X, and when the car returns to group B, the distance from point B to the starting point is Y..
Then [x-4 * (18-x-y)/60]/4 = (18-y)/60.
y/4 =( 18-x)/60+( 18-x-y)/60
So x=2 y=2.
Point A is 2 kilometers away from Beishan.
3. Peony Cup football match 1 1 round (that is, each team needs to play 1 1 game). If you win a game, you will get 3 points, if you draw a game, you will get 1 point, and if you lose a game, you will get 0 point. The team of Guoxing Sangao Club won four times as much as it lost, and the result was * * * 25 points. The team won the trophy.
Let x win and y lose, then 1 1-x-y will be even.
x=4y
3x+ 1 1-x-y=25
x=8
y=2
Eight wins and two losses 1 draw.
In extracurricular activities, some students take part in group activities. Originally, there were 8 people in each group, and then they were regrouped, with 12 people in each group, which decreased by 2 groups. How many students are there?
Suppose there is an X organization. So the number of people is 8x.
(x-2) 12=8x
x=6
* * * There are 48 people.
5. There is a high-speed wind belt above the surface 10 km. Suppose there are two planes flying at the same speed in this wind belt, and one of them flies from A to B, the distance is 4000 meters, which takes 6.5 hours; At the same time, another plane flew from B to A in only 5.2 hours. What is the average speed of the plane and the wind?
Let the average speed of the aircraft be xkm/h and the wind speed be ykm/h.
From the meaning of the question, we can see that there is headwind from A to B and tailwind from B to A, and the countable equation is:
x+y=4/5.2
x-y=4/6.5
Solution: x = 9/ 13, y =113.
6. A team travels at a speed of 5 kilometers per hour. Twenty minutes later, a correspondent caught up with the team at a speed of 15 km/h. How many hours will it take him to catch up with the team?
5*( 1/3)+5*X= 15*X
x= 1/6
6. A harvester harvests 12 hectares of wheat every day. Cutting 2/3 of the wheat field improved the efficiency by 5/4 times, so it was completed 1 day ahead of schedule. How many hectares of wheat fields are there?
Assuming that the wheat field is x hectares, because two thirds of it has been cut, there is still 1/3 left, and the equation is obtained:
( 1/3)x/ 12 =( 1/3)x/[ 12 *(5/4)]+ 1
Simplify:
(5/3)x=(4/3)x+60
( 1/3)x=60
x= 180
So the wheat field has 180 hectares.
7. Party A and Party B invest in the company according to the ratio of 2: 5, and agree to share the profits according to the investment ratio. If the profit in the first year is 14000 yuan, how much should Party A and Party B share respectively? Solutions of equations
Solution: let every minute be divided into X.
2X+5X= 14000
7X= 14000
X=2000
2X=4000
5X= 1000
So A gets 4000 yuan and B gets 10000 yuan.
8. According to the regulations of civil aviation, an ordinary class passenger can carry up to 20 kilograms of luggage for free, and the excess can be purchased at the ticket price of 15% with the baggage ticket. A passenger carries 35 kilograms of luggage, pays the air ticket and baggage ticket 1323 yuan, and asks for the passenger's air ticket fee.
Please do equations to solve application problems.
Set the fare to x yuan.
x+(35-20)* 1.5% x = 1323 x = 1080
(It should be 1.5% per kilogram, not 15%) It is impossible to charge that high. If it is so high, the calculation result is not an integer, which is not in line with the actual fare of the air ticket. If it is charged according to 15%, the answer is 407; if it is charged according to 1.5%, the answer is 6544.
9. When a store sells two goods with the same price, one of them gains 25% and the other loses 25%. Is it a profit or a loss to sell these two goods?
Solution: Suppose the prices of these two commodities are both X yuan.
Because the purchase price is x/(1+25%)+x/(1-25%) = 4/5x+4/3x = 32/15x.
The price is, x+x=2x.
32/ 15x & gt； 2x instant purchase price > price
So lose money
10. It takes 30 seconds for the train to completely pass the 300-meter-long iron bridge, and it takes 10 seconds to completely stay on the bridge. The length and speed of the train.
Solution:
l+300=30v
300-l= 10v
v= 15m/s
L =150m
Answer: vehicle length150m, speed15m/s. ..
Responder: Shan Lan-Trainee Magician Level 2 3-9 2 1:35.
Evaluation is closed.
Respondent: President of Yu No.1 Middle School, 13 grade, 7-29 15:00.
A workshop can produce 120 type A parts, 100 type B parts or 200 type C parts every day. Three A-type parts, two B-type parts and 65,438+0 C-type parts can be made into a set. Now it is required to produce the most complete set of products within 30 days. How many days does it take to produce three parts, A, B and C?
First, the application of decimal step addition and subtraction
1, 6.25 yuan for a math book and 5.86 yuan for a Chinese book. Two books and one * * *, how much is it?
2. A watermelon weighs 4.86 kg and a cantaloupe weighs 3.5 kg. How many kilograms is a watermelon heavier than a cantaloupe?
One-step multiplication and division of two decimal places 1 a kind of wool is 48.36 yuan per kilogram. How much is 3 kilos? Buy 0.6 kg?
2. A professional sericulture group raises 2 1 spring silkworm and one * * * produces1.24kg cocoon. How many kilograms of cocoons are produced per piece on average?
Three, three two-step calculation application problems with known conditions 1, Xiaohong read a story book for five days, reading 12 pages every day, but didn't read 38 pages. How many pages are there in this book? (Draw a line segment)
3 bags of flour and 3 bags of rice in the canteen. Flour is 25 kg per bag and rice is 50 kg per bag. How many kilograms of flour and rice are shipped?
3. The militia targeted the target, using 250 bullets for the first time, 320 bullets for the second time, and the third time was less than the sum of the previous two times 180 bullets. How many bullets were used for the third time?
Four, two-step calculation application problems under two known conditions
1. The school bought 45 boxes of colored chalk, and white chalk bought more than colored chalk 15 boxes. How many boxes of chalk do I buy?
2. An empty basket weighs 2kg, and there are 32kg peanuts in it. The basket for peanuts is empty.