Help me with a few math problems, help me with a math problem?

1.It is not difficult to calculate that the table is 64 yuan and the chair is 48 yuan, so B has 20 chairs.

2.On the opposite side, there are a total of 100 kinds, recorded as 1 100 points, 30 2 points, 8 5 points, according to this data feature, the single digit of 1,3,7,9 must not be constructed, so, there are a total of 4x10 kinds, that is, 1,3,7,9,11,13,17,19··· 91, 93, 97, 99, a total of 40 kinds.

3.It's a question of permutations. The topic is to put ABCD 4 books on the 1234 shelf, the condition is that A cannot be placed on the first floor, B cannot be placed on the second floor, C cannot be placed on the third floor, and D cannot be placed on the fourth floor

There are 4 in total! (This is a factorial sign, not an exclamation mark, which means multiplying from 1 to n, here it means 1x2x3x4=24) Of the 24 methods, there are 9 that meet the requirements: 2143, 2341, 2413, 3142, 3412, 3421, 4123, 4312, 4321.

For example, 2143 is a book placed on the 1234th floor, 2143 represents badc, and so on.

Table unit price: 320 5 = 64 (yuan).

Unit price of chairs: (3*64+48) 5=48 (yuan)320 (64-48)=20 (sets).

A: B originally had 20 chairs.

I can't understand the question 1! ~—

2。I don't understand it at all.

3。How many floors are there? How many books can I put on the first floor?

Occupy other people's time and don't give 1 point to Ah <

It is known that 10,000 yuan is deposited at the beginning of each year, with an annual interest rate of 2%, and it has been deposited for 10 consecutive years. Using the final value factor formula, we can calculate the total principal and interest at the end of the 10th year. Known (f a, 2%, 10) ridge difference = .

The formula for calculating the final value factor (fa) of an annuity is:

f = p * f/a, i%, n)

Among them, F is the final value, P is the deposit (10,000 yuan deposited at the beginning of the year), I is the annual interest rate (2%), N is the number of periods (10 years), and (F a, i%, n) is the final value factor of the annuity.

Substituting the known conditions into the formula, we can calculate the total principal and interest at the end of the 10th year:

f = 10,000 * = 109,500 RMB.

Therefore, at the end of the 10th year, Yuye Travel can withdraw a total of 109,500 yuan of principal and interest at one time.

At the beginning, it was only counted for a year, and there were mistakes, so change it) may want to be a little more complicated:

a. If the bank interest is not calculated with compound interest: you can take out 10000 + 10000 x 2% x 10 + 10000 + 10000 x 2% x 9 + .10,000 + 10,000 x 2% = 100,000 + 10,000 x 22% * 5 = 111,000, of which the principal is 100,000 yuan and the interest is 11,000 yuan.

b. If the bank calculates the compound interest of the branches: you can take out 10000x(1+2%) 10+10000x(1+2%) 9+.10,000x(1+2%)=, where the principal is 100,000 yuan and the interest is 11,687 yuan.

The 10th year of tremor can be taken out at one time....The "10th year" should read "the 10th year of this withering."FinalWell, it should mean "year-end" - the following answer:

Deposited at the beginning of each yearEqualFunds, belongsPrepaid annuities。This question is a questPrepaid annuity cave final value, for:

fa=a (f a,i,n) (1+i) 10000 (f a,2%,10) (1+2%) 10000 111690 (yuan).

Every year, I deposit 10,000 yuan to the bank at the beginning of the year and save it for ten consecutive years, which is the cost, even if the interest of 100,000 yuan is more than 30,000 yuan.

This calendar is a topic for summing up a series of proportional numbers. Collapse search.

Hello, you are looking for the final value of the prepaid annuity; The title gives (f a,2%,10)=, the final value coefficient of the annuity for 10 years with a 2% interest rate on behalf of Xunzhao table; Because it is deposited at the beginning of each year, it is a pre-round travel annuity: 10,000*.

According to the calculation of compound interest with Changyan, the principal and interest can be withdrawn quickly in the 10th year.

10,000 yuan

Just let the university faculty do it.

It can be obtained by 2x+y"Jane Lu = 11, x + 2y < = 10.

2x+4y-2x-y<=20-11 Solve y<=34x+2y-x-2y<=22-10 Solve x<=4 Because y has the highest profit band, all y values should be as large as possible.

So stool y takes 3 and x takes 4

2x+y≤11 (1')

x+2y≤10 (2')

x 0 Qingbi (3')

y≥0 (4')

max z=8x+10y

solution

2x+y=11 (1)

x+2y=10 (2)

x=0 (3)

y=0 (4)

case 1: (1) and (2)

2x+y=11 (1)

x+2y=10 (2)

3y = 9

y=3from (1)

x=4x,y)=(4,3) satisfies (3'),4')

z=8x+10y

z(4,3) =32+30 =62

case 2: (1) and (3)

2x+y=11 (1)

x=0 (3)

x,y) =0, 11)

x,y)=(0,11) does not satisfy (2')

Case 2 Withhold.

case 3: (1) and (4)

2x+y=11 (1)

y=0 (4)

x,y)=(11/2, 0)

x,y)=(11 2, 0) satisfies (2'),3')

z=8x+10y

z(11/2, 0) =44+0 =44

case 3: (2) and (3)

x+2y=10 (2)

x=0 (3).

x,y) =0,5)

x,y)=(0, 5) satisfies (1'),4')

z=8x+10y

z(0, 5) =0+50 =50

case 4: (2) and (4)

x+2y=10 (2)

y=0 (4)

x,y) =10,0)

x,y)=(10, 0) does not satisfy (1')

Case 4 : Discarding.

case 5 ：(3) and (4)

x,y)=(0,0)

x,y)=(0, 0) satisfies (1'),2')

z=8x+10y

z(0, 0) =0+0 =0

So max z : case (1).

z(4,3) =32+30 =62

From the second group, we can see that the weight of the square + circle is 11 kg, combined with the first group, the triangle is 12 kg, and the third group is combined to get the circle is 4 kg, so the square is 7 kg. x+y+z=23

2y+2z=23

2x+z=28

24 (3-1) = 12, Xiaohong is 12 years old, and Mom is 36 years old.

1. Assuming that there are x black balls, the probability of getting the white ball is 3 (x+3), and the probability of getting the black ball is x (x+3).

300*3 (x+3)=57, let the high x be approximately equal to 13500*x (x+3)=398Then x is approximately equal to 122, a table tennis ball of one color taken out? Yellow?

White? Same color? Different colors?

Please complete the form.

The area of the inner circle is.

The shaded area is.

The shadow side is larger than the inner circle mask, so the game is not fair and beneficial to Red.

1. Set a minimum discount of x.

2800*x/100≥2000(1+5%)28x≥2100

x 75 can be discounted as low.

2. Nickname x Lee, X-4, Sakura x+3

x+x-4+x+3-7*3<29 3x-22<29 3x<61 x<20 and 1 3

x+x-4+x+3+4*3>56 3x+11>56 3x>45 x>15

So 151, so 1, and the coordinates are integer, so a=2