There are 3 meadows, 5 hectares, 15 hectares, and 24 hectares, and the grass on the meadows is as th

From the inscription, if the first plot of land is 15 hectares, then it can be eaten by 30 heads for 30 days, and the amount of food that a cow can eat in a day is the unit "1".

Then the amount of grass grown in one day on 15 hectares of land is [28*45-30*30] [45-30]=24 units.

That is, the third plot of land can feed 42 cows for 80 days.

Equation for each cow to eat x hectares of grass per day.

The second plot grows twice as fast as the first.

2 (24*6x-4) 6 (36*12x-8) 12 solution x 1 6

The grass grows at a rate of (36*12*1 6-8) 12 16 3 ha week.

10 (50*1 6-16 3) 10 3 weeks.

It's not necessarily right, you check it yourself, after all, you haven't touched a cow and eaten grass for a long time.

40 25 = 1000 (square meters).

1 hectare = 10,000 square meters.

10000 1000 = 10 (block).

A: 10 of these meadows are about 1 hectare

So the answer is: 10

Sheep grazing problems.

With the inscription that 5 hectares of grass can feed 11 cows for 10 days, we can launch 30 hectares of grass for 66 cows for 10 days. Similarly, the second plot of 6 hectares can feed 12 cows for 14 days, i.e. 30 hectares can be considered to feed 60 heads for 14 days.

Let's assume that 1 cow eats one unit of grass in 1 week, so the growth on the pasture in (14-10) days is 60*14-66*10=180 units, so the growth in the pasture in 1 day is 180 4=45 units. From this, we can calculate that there are 66 * 10 - 10 * 45 = 210 units of grass on 30 hectares of grassland.

Thus, there are 8 hectares of grassland with 210 * (8 30) = 56 units of grass on it, and the 1-day grassland increment of 8 hectares of grassland is 45 * (8 30) = 12 units.

In summary, 19 cows can be fed on 8 hectares of pasture: 56 (19-12) = 8 days.

Finally, the increment of grassland for 8 hectares in 1 day is 12 units, and a total of 14 * 12 = 168 units in 14 days. Adding the original 56 units, a total of 224 units, divided by 14 days, equals 16 cows.

9 weeks. I should be able to make the land the same:

4 hectares of 24 cattle for 6 weeks = 2 hectares of 12 cattle for 6 weeks.

8 hectares 36 cows for 12 weeks = 2 hectares for 9 cows for 12 weeks.

10 males of Laqingdan, 50 heads of molds or cattle eat weeks = 2 hectares of 10 cows eat weeks.

Equation for each cow to eat x hectares of grass per day.

The second plot grows twice as fast as the first.

2 (24*6x-4) 6 (36*12x-8) 12 solution x 1 6

The rate at which the grass grows is (36*12*1 6-8) 12 16 3 hectares Week 10 (50*1 6-16 3) 10 3 weeks is not necessarily right, you check it yourself, after all, you haven't touched a cow to eat grass for a long time.

4 hectares 24 cows eat for 6 weeks --》You can get 8 hectares of land 48 cows eat for 6 weeks (36x12-48x6) (12-6) = 24 (8 hectares of grass growth rate).

36-24) x 12 = 144 (8 hectares of grass) 144 8x10 = 180 (10 hectares of grass) 24 8x10 = 30 (10 hectares of grass).

180 (50-30) = 9 weeks.

Let each cow eat grass per week as "1".

6 weeks per hectare: 24*6 4=36

12 weeks per hectare: 36*12 8=54

One hectare of new grass per week: (54-36) (12-6) = 3 The amount of raw grass per hectare: 36-3 * 6 = 18

Ten hectares of raw grass: 18*10=180

10 hectares of new grass: 3*10=30

180 (50-30) = 9 weeks.

Because of the different areas, the amount of growth in each meadow is also different, but the growth rate per hectare is the same.

Let's say 1 cow eats 1 serving in 1 week. Then 24 cattle per hectare eat for 6 weeks: 24x6 4=36 (portions) 36 cattle per hectare eat for 12 weeks:

36x12 8=54 (portions) Daily growth: (54-36) (12-6)=3 (portions) The amount of raw grass per hectare is: 36-3x6=18 (portions) 50 cattle per hectare per week:

50 10 = 5 (portions) minus the amount of grass grown per day: 5-3 = 2 (portions).

The amount of raw grass per hectare divided by the amount of grass eaten per hectare per week gives the number: 18 2 = 9 (weeks).

Let the rate of grass grow per hectare per week is n, 1 cow grazing per week is m, and the original grass of 1 hectare of grassland is a.

24x6m=4x6n+4a

36x12m=8x12n+8a

The relationship between m and n,a is derived.

n=3m a=18m

Let the third piece of grassland be used for x cows for 20 days, x*20*m=10*20*n+10a, and use m for n and a

substitution, and the solution is m=

The growth rate of grass is determined to be invariant.

Suppose each cow eats x hectares of grass per day.

24*6x-4) (6*4) (36*12x-8) (12*8) solution x 1 18

Substituting the original equation yielded a growth rate of 1 6 ha per week.

10 (50*1 18-10*1 6) 9 weeks.

The height of the grass is x meters, and the speed of grass growth is y meters per day. Column equations.

The first plot: 5(x+30y)=10*30

The second plot: 15 (x+45y) = 28*45

The third plot: 24 (x+80y) = z*80

Find: x=12, y=, z=42

Answer: The third plot of grass can feed 42 cows for 80 days.

Assuming that the daily grass growth ratio per hectare is x (1 relative to the original grass per hectare), the third grass can be eaten by Y cattle for 80 days.

5+30*5*x）/（10*30）=（15+45*15*x）/（28*45）=（24+80*24*x）/（80y）

x=2/15，y=42

This is also a matter of cattle grazing, where the key is to make the grass area the same.

Since the smallest common multiple is 120, the area of the first meadow can be increased by 24 times, and the number of cattle can be increased by 24 times, so that there are 120 acres of meadow for 240 cows to eat for 30 days.

The second plot of land was treated in the same way: 120 acres of grassland for 224 cows to feed for 45 days.

So the question becomes:

A 120-acre meadow can feed 240 cows for 30 days, or 224 cows for 45 days, how many cows can eat this meadow for 80 days?

Let's say a cow eats 1 unit of grass in a day.

Then for the first meadow, 240 cows eat for 30 days and consume 240 30 7200 units.

For the second meadow, 224 cows eat for 45 days and consume 224 45 10080 units.

As a result, the grass grows in the meadow every day: (10080 7200) (45 30) 192 units.

Grass in the grass: 10080 192 45 1440 units.

The third enlarged plot of land was available for: (1440 192 80) 80 210 head of cattle.

It can be seen that 120 acres of grassland can feed 210 cattle for 80 days, so 24 acres of grassland can feed 42 cattle for 80 days.

Let each cow eat x amount of grass per day

Then there is the first meadow for 10 cows to eat for 30 days.

Therefore, the sum of 5 acres of grass and the amount of grass grown in 30 days of 5 acres of land is 300 x the second piece of grass can be eaten by 28 cows for 45 days.

The amount of grass on 5 acres of land is 60x

The amount of grass in one acre of land is 12x, and the amount of grass that grows in one day is 8 5x, so the amount of grass in the third plot is 24*12x=288x80x80, and the amount of grass grown in 80 days is 24*80*8 5x=3072x, so the total amount of grass that can be eaten by cattle in the third plot for 80 days is 3360x, and the number of available cattle is 3360x, 80x=42