Please help solve the math problem, thank you!

11.A takes 8 hours to walk from A to B, B takes 6 hours to walk from B to A, A and B start from A and B at the same time, go in the opposite direction, pass (

Hours meet. Solution: Let's meet after x hours.

1/6)x+(1/8)x=1

4x+3x=24

x=24/7

12.If a steamship sails at the same stillwater velocity in a river with a current velocity of 2 km, it is known that the time taken by the steamer to sail 10 km against the water is the same as the time taken to sail 14 km downstream, find the velocity of the ship in still water, if the speed of the ship in the still water is x km, then the equation listed is (, and the water velocity is () solution:

14/(x+2)=10/(x-2)

x=12A: 13The eighth-grade students of a certain school were conducting marching training, and they planned to travel a distance of 36 kilometers and arrived at 5 p.m., but in the actual marching training, because the marching speed was 1 5 faster, the result was that they arrived at 4 p.m., what was the planned marching speed?

Solution: If the planned marching speed is x, then the actual marching speed is (1+(1 5))x=(6 5)x

36/x-36/(6/5)x=5-4

36/x-30/x=1

6 x = 1 x = 6 A:

14.Xiao Ming.

's mother bought a number of bottles of yogurt with yuan in a store, and later she found in a shopping mall supermarket that the same yogurt was cheaper than the store per bottle, and she used yuan to buy yogurt, and the number of bottles of yogurt she bought was 60 more than the last time, how many bottles of yogurt did Xiao Ming's mother buy in the store for the first time?

Solution: Suppose Xiao Ming's mother bought x bottles of yogurt in the store for the first time, then Xiao Ming's mother bought (1+60%) x = bottles of yogurt in the store for the second time.

1 x=x=5A:

15.Certain. Water Company.

The water fee is calculated as follows: if the monthly water consumption of each household does not exceed 5 tons, the water fee will be charged per ton; If it exceeds 5 tons, a higher fixed fee will be charged for each ton. Known in July.

The ratio of Xiaoying's water consumption to Xiao Ming's water consumption is 2:3, Xiaoying's monthly water bill is yuan, Xiao Ming's family is yuan, and how much yuan is charged per ton for the part exceeding 5 tons?

Answer: The part exceeding 5 tons is charged x yuan per ton, the water consumption of Xiaoying's family in July is 2y, and the water consumption of Xiaoming's family in July is 3y

Finishing (1) (2).

x(2y-5)=

x(3y-5)=

xy=(5)*3-(4)

5x=x=A:

The number A is the number B 16 15; This number is 39 16;It costs 30cm on the map; The actual length should be.

Solution: Let A be 7x yuan and B be 3x yuan.

7x+700）：（3x+700）=7：428x+2800=21x+4900

7x=2100

x=3007x=2100

3x=900

A: A was originally 2,100 yuan, and B was 900 yuan.

A: B = 3 4:4 5 = 15:16

So A is 15 16 of B

1500km=150000000cm

150000000×1÷50000＝15000cm35×1÷5＝7

(1) Solution:

Let A do 1/x per day, and B 1/3 x per day.

You can get it by knowing.

x/2=x+3/3

This gives us x=6

So the prescribed number of days is 6 days.

Set: The price of each garment is X yuan, and the cost is Y yuan.

According to the title:

0,8x-y=40

Simultaneous solution x=200

y=120y/x=

So up to six percent off.

1. Set the price of x yuan and the cost of y yuan, then solve the system of equations to obtain x=200 y=120

The price of each garment is 200 yuan, and the cost is 120 yuan.

2. In order to reduce inventory, the lower the price, the better, to ensure that there is no loss, the price is more than 120 yuan, so the price is 120 yuan.

120%200= So the sheet is discounted at a maximum of 6%.

lz, the answer is as follows:

1) Set the price to be $ x and the cost to be $ y; Then: , obtained: x=200 yuan, y=120 yuan;

2) If you want to reduce as soon as possible, you must be better at the end of the month, and you must not lose money, then set the discount to a discount and find the minimum value of a.

So 200a-120 0

Get a so a takes, that is, 6% off.

(40+20) divided by (80%-50%) = 200 yuan.........Price.

200 times 80%-40 = 120 yuan .........Cost.

120 divided by 200 = 60% = 6% off So up to 6% off.

Let the list price be x and the cost be a system of y-column equations.

Solution: x=200, y=120

Set up to Z discount.

200z 10=120 solution Z=6, six discounts.

Question: 120% x = solution of the equation.

Question: 48%x = solution to the equation to solve the equation.

Question 5 + 90% x = 41 to solve the equation.

Have you ever seen such a cheap teacher?

10 yuan = 1000 points Suppose you buy 50 cents of stamps, a total of 50 35 = 1750 cents, so that the actual 1750-1000 = 750 cents less than the assumption. And a 20-cent stamp is 50-20 = 30 cents less than a 50-cent stamp, therefore, the number of 20-cent stamps is 750 30 = 25, and a 50-cent stamp is 35-25 = 10 stamps. In the same way, you can also find the number of 50-cent stamps first.

Comprehensive formula: (50 35-1000) (50-20) = 25 sheets.

35-25 = 10 sheets.

If 20 points are x, and if 50 points are y, then x+y=35,, solve x=25, y=10

20 points x sheets, 50 points y sheets.

From the meaning of the title. x+y=35

The solution is x=

Solution: Set 20 cents stamps to buy x sheets, 50 cents stamps to buy 35-x 20x+50(35-x)=10 100

x=2535-x=35-25=10

A: 25 stamps were bought for 20 cents and 10 stamps for 50 cents.

Assuming that 20 points of x sheets, then 50 points of (35-x) sheets, resolution of 10 yuan = 1000 points, column formula 20x + 50 (35-x) = 1000

20x+50*35-50x=1000

30x=750

x = 25 tickets, i.e. 25 tickets out of 20 points.

35-25 = 10 sheets, that is, 10 sheets out of 50 points.

I don't know.

It's all about learning. I've eaten my meal.

It's long forgotten.

The first question is to make the sum of the three numbers a multiple of 9. Such numbers can be divided into three groups of 16. 2) Second question:

In general, from the lower left corner of a row of n squares in a m column to the upper right solution (only going up or to the right), there are a total of a(m+n,m+n) [a(m,m)*a(n,n)] moves. So there are *60 kinds in this question. where a(n,n)=n!

1. The multiple of 9 in the three-digit number, the sum of the characteristic three-digit number is 9

There are six kinds (i.e., 126, 162, 216, 261, 612, 621);

six kinds; Outline. six kinds; Outline.

Four types; Outline. Four types; Outline.

A total of 3*6+4*2=26 types.

2. There are 10 kinds from A to E, and there are 6 kinds from E to B, so there are 10 * 6 = 60 kinds of Heng Nian Yu Group: 10 * 6 = 60 kinds.

The first question is not very clear about what the "number of weighings" in the middle means. Weigh up to a few times, from top to bottom: 2, 2, 3, 3

The second question is divided into three parts, each serving is 3 boxes, and each copy is numbered A, B, and C. Weigh two parts A and B, and if balanced, the side is in part C; If unbalanced, side in a lighter serving, such as A. Determine which part it is, and then weigh two of them, and if it is balanced, it is the last part; The imbalance is the lighter one.

Question 3, 10 bags of sugar are divided into 4 parts: 3 bags of sugar for A, B, and C, and 1 bag of sugar for D;

First call A, B two parts: balance.

The side is called A and C in two parts.

balance, then it is part d.

If it is unbalanced, it will be in two of the lighter parts, the C parts, and then the C parts.

balance, then in a bag that is not weighed.

unbalanced, then in a lighter bag.

If it is unbalanced, set up two bags of A and then weigh A in the lighter portion.

balance, then in a bag that is not weighed.

unbalanced, then in a lighter bag.