There are 20 application problems for one dimensional quadratic equations groups .

One. There is a pasture where the grass grows at a uniform rate every day (the grass grows by the same amount every day) and if 24 cattle are grazing, the grass is eaten in 6 days. If 21 cattle are grazed, then after 8 days, let each cow eat the same amount of grass per day, Q:

1. If you graze 16 cows, can you eat hungry reed grass in a few days? 2. If you want to never eat the pasture, at least how many cows can you graze? Two.

Meetings are arranged for people to stay, and if 6 people live in each room, 8 people have no accommodation; If there are 7 people in each room, exactly 2 dormitories will be vacant, and the number of participants and the number of dormitories will be found. Three. There are 27 people working in A and 19 people working in B, and now another 20 people are transferred to support, so that the number of people in A is twice as many as the number of people in B. How many people should be transferred to A and B?

Four. It took 2 hours for a boat to travel downstream from pier A to pier B, and 3 hours to sail against the current from pier B to pier A; It is known that the distance between piers A and B is 60km, and the speed of the ship in still water and the speed of the current are found. Five.

An airplane flies between cities A and B, which are 2448 km apart, and it takes 2 hours and 50 minutes to fly downwind from A to B, and 3 hours to fly upwind from B to A. Six. A pipe gushing occurs in a depression on the side of a river embankment, and the river water continues to gush out, assuming that the amount of water gushing out is the same every minute, if two pumping machines are used, the pumping will be completed in 40 minutes; If you use four pumps, it will take 16 minutes.

If you want to deal with a dangerous situation as quickly as possible and get the water pumped in less than 10 minutes, how many pumps do you need? Seven. There are two types of trucks A and B, 2 A type cars and 3 B type cars can transport tons of goods at a time, 5 A type cars and 6 B type cars can transport 35 tons of goods at a time, so how many tons can 1 A type car and 1 B type car transport a total of 2 tons?

Eight. There are 22 workers in a workshop, each person can produce an average of 1,200 snails or 2,000 nuts per day. Nine.

A and B are 6km apart, and they set off at the same time and travel in the opposite direction, meeting in 1 hour; At the same time, start in the same direction, A can catch up with B in 3 hours. What is the average speed of each of the two tens. Someone running along the road and keeping an eye out for a bus coming from the back to the front every 6 minutes and a bus coming from the opposite side every 2 minutes, if the speed of the person and the bus is the same, and every few minutes a bus departs from the bus terminal?

8.There are two kinds of bonds, A and B, with an annual interest rate of 10% and 12% respectively, and the existing bonds are 400 yuan, and the profit is 45 yuan after a year.

1.There are 3 kinds of packaging of a drink, 1 medium bottle is cheaper than 2 small bottles 2 jiao, 1 large bottle is more expensive than 1 medium bottle plus 1 small bottle 4 jiao, large, medium and small buy 1 bottle each, it costs 9 yuan and 6 jiao. How much is each bottle of the 3 types of beverages in packs.

2.A class of students went on an outing of 18 kilometers to Beishan. There is only one car, and it needs to be divided into two groups, group A takes the car first, and group B walks.

The car goes to place A, group A gets off and walks, the car returns to pick up group B, and the last two groups arrive at Beishan Station at the same time. When the speed of the car is 60 kilometers and the walking speed is 4 kilometers, find the distance between point A and Beishan Station.

3.Level 1 students go to the cafeteria for a meeting, if every 4 people sit on a bench, 28 people have no place to sit, if 6 people sit on a bench, find the number of students in the first level and the number of benches.

4.If two trains depart at the same time from two opposite directions at a distance of 910 kilometers and meet 10 hours later, if the first train departs 4 hours and 20 minutes earlier than the first and second trains, then they meet 8 hours after the departure of the second train, and the speed of the two trains is found.

5.A book and 16 books B were purchased for a total of 410 yuan, and the A book was 15 yuan more expensive than the B book.

6.A and B respectively set off from A and B at the same time, and B met for the first time when A exceeded the midpoint 50 meters from A, and A and B arrived at B, and A immediately turned back and walked back, and as a result, A and B met for the second time at a distance of 100 meters from A, and sought the distance between A and B.

But I can't give you the answer, but I'm guessing you're doing the exercises, and you can test the answer yourself, and it's like this for binary equations.

Set up an electronic whiteboard is the first is x yuan, and the first of a projector is y yuan, according to the problem to get the following equations.

2x-3y=4000 (1)

4x+3y=44000 (2)

1) +(2) 6x=48000 => x=8000 (yuan) substitute x=8000 (yuan) into (1), get y=4000 (yuan) Answer: The ** of an electronic tabula rasa is 8000 yuan, and the ** of a projector is 4000 yuan.

Let the speed of the passenger car be XM S and the truck speed is YM S

Because it is known that the blind cherry surplus condition 2 is that the passenger car catches up with the truck, so x>y21(x+y)=1050

105(x-y)=1050

The solution yields x=30 y=20

Det 30m s for passenger car 20m s for cargo song

If you need to solve this equation or have other questions, please ask me

1. The speed of the boat in still water x

km h, the velocity of the water flow y

km/h:80=

80=x=45km/h,y=5km/h

Suppose we add a metal x kilogram, and it turns out that this alloy contains a metal yx+y) (10-y)=3 2

2x+y)/(10-y)=7/3

x=5y=4

Add 5 kg of formametal.

It turns out that the percentage of A metals in this alloy is 4 10 = 40% 3, as; Flat road length x

km, slope length y

km according to the title: x 60 + y 30 =

x/50+y/40=6

Solve the rock and get the thick code: x=150

y=120, the total distance is x+y=270km

A: The school is located 270 km from the nature reserve.