Math Master, SOS!! 100

Uncle Wang, a villager, has 3 female foxes, they gave birth to 18 young foxes, and the cubs produced are calculated as 2 5 female foxes, (according to a female fox giving birth to cubs once a year), female foxes can give birth to cubs when they are one year old. Uncle Wang wants to build a farm with 70 foxes, how many years will it take?

Total number of foxes in the second year: 3+18+18*2 5*1=

Among them, the number of female foxes: 3+18*2 5+18*2 5*1*2 5=

Total number of foxes in the third year: 3+18+18*2 5+3+18*2 5+18*2 5*2 5*2 5=

Among them, the number of female foxes: 3+18*2 5+18*2 5*1*2 5+(3+18*2 5+18*2 5*1*2 5)2 5=

Total number of foxes in the fourth year: 3+18+18*2 5+3+18*2 5+18*2 5*2 5+3+18*2 5+18*2 5*1*2 5+(3+18*2 5+18*2 5*1*2 5*1*2 5)2 5=

The total number of female foxes: 3+18*2 5+18*2 5*1*2 5+(3+18*2 5+18*2 5*1*2 5*1*2 5)2 5+[3+18*2 5+18*2 5*1*2 5+(3+18*2 5+18*2 5*1*2 5*1*2 5)2 5]=

Total number of foxes in the fifth year:

So it takes about five years.

3 female foxes gave birth to 18 cubs (7 females).

So the nth year. (female) + (male) = total 5 years.

Within 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 o( o Hehe, just kidding.

I calculated that it was 5 years, and the algorithm was the same as that of Desert My Love Fruit...

Total number of foxes in the second year: 3+18+18*2 5*1=

Among them, the number of female foxes: 3+18*2 5+18*2 5*1*2 5=

Total number of foxes in the third year: 3+18+18*2 5+3+18*2 5+18*2 5*2 5*2 5=

Among them, the number of female foxes: 3+18*2 5+18*2 5*1*2 5+(3+18*2 5+18*2 5*1*2 5)2 5=

Total number of foxes in the fourth year: 3+18+18*2 5+3+18*2 5+18*2 5*2 5+3+18*2 5+18*2 5*1*2 5+(3+18*2 5+18*2 5*1*2 5*1*2 5)2 5=

The total number of female foxes: 3+18*2 5+18*2 5*1*2 5+(3+18*2 5+18*2 5*1*2 5*1*2 5)2 5+[3+18*2 5+18*2 5*1*2 5+(3+18*2 5+18*2 5*1*2 5*1*2 5)2 5]=

Total number of foxes in the fifth year:

So it takes about five years.

Alas, why do you copy each of them?

3 female foxes gave birth to 18 cubs (7 females).

So. Nth year. (female) + (male) = total.

Therefore, it should take 4 years.

The income and expenditure of the Zhang family are:

8 incomes - 8 expenses 240 yuan.

Therefore: 1 income - 1 expenditure 240 8 30 yuan because "the ratio of the income of the Zhang family to the Li family this month is 8:5, and the ratio of the amount of money spent this month is 8:3".

Therefore, the income of the Li family is 5 8 of the Zhang family, that is, 5 incomes, and the expenses of the Li family are 3 8 of the Zhang family, that is, 3 incomes.

So the income and expenditure of the Li family is:

5 incomes - 3 expenditures 510 yuan.

Turn the Li family's income and expenditure into:

2 incomes, 3 incomes-3 expenses, 510 yuan.

Because "1 income - 1 expenditure 30 yuan".

So 3 incomes - 3 expenses 30 3 90 yuan.

The money for 2 incomes is:

510-90 420 yuan.

1 income is:

$420 2 210.

Therefore, the income of the Zhang family is 8 shares, and the income is:

210 8 1680 yuan.

The income of the Li family is 5 shares, and the income of the money is:

$210 5 1050.

The height of the cone is h, and the height of the cylinder is (36-h).

Conical ground area: cylindrical base area = 3:2

Then: (1 3 3 h) [2 (36-h)]=2:5 solution: h=16

Then the height of the cone is 16 centimeters.

1: Analysis.

Assuming that the ratio of the Zhang family and the Li family this month is 8:3, then if the Zhang family balance is 240, the Li family's balance [240 divided by 8 times 3] = 90

This is because the income ratio is the same as the monthly expense ratio, then he is also equal to the balance ratio, and the current ratio is income 8:5, then the Li family's extra money (5-3) = 2 cents is 270-90 = 180

Then the income of the Li family is 180 divided by 2 and then multiplied by 5 = 450, and the income of the Zhang family is 450 times 8 5 = 720

2: Analysis. The height of the cone = 3 times the volume area.

The height of the cylinder = volume divided by area.

Then the ratio of the height of the cone to the cylinder = (2 times 3 divided by 3) :(5 divided by 2) = 4:5, then the height of the cone = 36 divided by (4 + 5) and multiplied by 4 = 16

1.Solution: Li family's income = [270-(240*3 8)]*5 (5-2)=450

Zhang's income = 450 * 8 5 = 720

2.Solution: Cylindrical volume = base area * height, cone volume = base area * height 3 high ratio = volume ratio base area ratio = 3 * (2 5) (3 2) = 4 5 so cone height = 36 * 4 (5 + 4) = 16 cm.

Original = square of (x-2) - (1+x-1) * (1-x+1) (x-2) = square of (x-2) - x

x squared - 5x+4

and the square of x-5x-2010=0

Original = 2010 + 4 = 2014

Solution: According to the question, it can be obtained: it is divided into two situations, start rowing downstream or start rowing upstream;

Let's assume that we start with a downward row, and if we paddle for 30 minutes, we will paddle downstream (3+km);

When returning, row upstream for half an hour, drift down the river for 10 minutes as a cycle, you can row upstream (km);

I can't get back to the charter for the remaining 40 minutes

Assuming that he starts rowing downstream for x (x 30) minutes, then in the first 40 minutes, he can row downstream (3+ km) to ensure that he can return to the charter, then he is required, i.e. x 15;

So you can row up to (3+km);

At the beginning, row upstream, so you have to row upstream for half an hour, drifting along the river for 10 minutes as a cycle, (t=40 minutes);

You can paddle upstream (km);

Assuming that you can row 2 40+x (x 30) minutes upstream, you can row 2 upstream;

The rest of the time can be rowed downstream (3+;

To ensure that you can return to the charter, you need 1+x40, and solve x15;

So you can leave the charter up to 1+1540=km);

Comparing the two cases, it is possible to leave the charter for up to a maximum of kilometers

A: Xiaohu's boat can be as far away as a kilometer from the charter office

You should have also learned the sine theorem, I used the triangle area formula s=1 2absinc

eg/ga=(1/2*ec*gc*sin∠ecg)/(1/2*ac*gc*sin∠acg)

ec*sin∠ecg）/(ac*sin∠acg)

ec/ac)*(sin∠ecg)/(sin∠acg)

Similarly, EF FD = (EC DC)*(SIN ECG) (SIN ACG).

Therefore, (sin ecg) (sin acg) = (ef fd)*(dc ec).

Therefore eg ga = (ef fd) * (dc ac).

And because F is the vertical center of a right-angled triangle ECD.

It's just a bunch of triangles that resemble.

ef/fd=ec2/dc2

eg/ga=ec2/(ac*dc)

The next thing is simple, connect EB, triangle ABE is a right triangle again, a bunch of similar triangles.

bc/ec=ec/ac

bc=ec2/ac

So bc dc=(ec2 ac) dc=ec2 (ac*dc)=eg ga

i.e. bc dc = eg ga