Find answers to a few math questions. Urgent!!!

2. In order to have the smallest natural value, the number of digits must be as small as possible.

2005=9+9+9+9+9+..9 (222 of 222) +7

The minimum number is 9999....9 (221 of 221) 7

Therefore, n minimum is 223 digits.

3. Solution: The tour group is set to live in triple room x room, double room y room, single room z room, and the total accommodation fee is a yuan

From the meaning of the title, {x+y+z=20 3x+2y+z=50 60x+60y+50z=a

From - we get 2x+y=30, i.e. y=30-2x

From -2 we get x-z=10, i.e. z=x-10

0 y 20, i.e. 0 30-2 x 20, gives 5 x 15

In the same way, 0 z 20, i.e., 0 x-10 20, gives 10 x 30

by Zhi 10 x 15

Substituting a=60x+60(30-2x)+50(x-10)=1300-10x?x=130- a10

10≤ 130-a10≤15?1200≤a≤1150

The most economical accommodation cost is 1150 yuan, at this time x = 15

Then substituting the value of x into y=0, z=5

So the answer is 1150, 15, o, 5

4. Solution: Let the water of pool B be 4 times that of pool A after x hours, there is 4 * (960-600x) = 90 + 600x, and the solution is x =, that is, 1 hour and 15 minutes.

Do you give points?

1.The maximum is 17993 and the smallest is 3005

Number of digits. 14, 2, and 4 for a human being, a 2-person room, and a 1-person room, respectively

Hour 15 minutes.

-2005=7994, so the sum is up to 9999+7994=17993

2005+1000=3005, so the sum minimum is 3005+1000=4005

9*222+7, so the minimum n is 223 digits.

3. There are 3 rooms in x room, 2 rooms in y room, and single room (20-x-y) room (where x, y, 20-x-y are all integers from 0 to 20).

From 3x+2y+(20-x-y)=50, we know that 2x+y=30, y=30-2x

Because y=30-2x>=0, x<=15

The total cost is 20*3x+30*2y+50*(20-x-y)=10x+10y+1000=1000+10x+10*(30-2x)=1300-10x>=1300-150=1150

Therefore, the minimum total accommodation fee is 1150, and 15, 0, and 5 rooms for 3 rooms, 2 rooms, and 1 person rooms are respectively.

4. After setting x hours, the water in pool B is 4 times that of pool A, with 4 * (960-600x) = 90 + 600x, and the solution is x =, that is, 1 hour and 15 minutes.

2 2005 9 = 222 remainder 7 n = 223

3 2, 3 rooms at the most, the minimum fee is 10 rooms, 2 10 rooms, 3 rooms, 500 at this time

4 After x hours, then 4(960-600x)=(90+600x) x=373 300

1.40*(1+25) 1=1040 (kg).

2.Boys: 6 (1-3 5) = 15 (people); Girls: 15-6=9 (people).

3.[120 (2 5)]*1-2 5)*[4 (4+5)]=80 (Ben).

1. Car A and car B are traveling in opposite directions from two places 700 kilometers apart at the same time, and after 4 o'clock when they meet, it is known that the speed of car A is twice that of car B. What is the speed of each vehicle A and B.

Speed sum = 700 4 = 175 km h.

Car B = 175 (1+kmh.)

Car A = 70*km hour.

2. 72 students from Yuhua Primary School go on a spring outing, how to rent a car? The first car is limited to 15 people at 400 yuan per vehicle per day, and the second car is limited to 29 people at 500 yuan per vehicle per day.

72 15 = 5 cars 400 * 5 = 2000 yuan.

72 29 = 3 cars 500 * 3 = 1500 yuan 29 * 2 + 15 = 58 + 15 = 73 500 * 2 + 400 = 1400 yuan.

You can rent two 29-person cars and one 15-person car for 1400 yuan a day.

3 Wang Liang In the final exam, the average score of Chinese and Mathematics was 94 points, the average score of Mathematics and English was 92 points, and the average score of Chinese and English was 90 points. In this exam, how many points did Wang Liang score in each of these three courses?

Chinese + Mathematics = 94*2

Mathematics + English = 92*2

Chinese + English = 90*2

Chinese + Mathematics + English = 94 + 92 + 90

Language = 94 + 92 + 90-92 * 2 = 92

Mathematics = 96 English = 88

4 Uncle Wang used yuan to buy 3 kilograms of lychees and 4 kilograms of longan, and it is known that the price of 5 kilograms of lychees is equal to the price of 2 kilograms of longan, how many yuan per kilogram of lychee and how much yuan are each of each kilogram of lychee and kilogram of longan?

The price of 5 kilograms of lychee is equal to the price of 2 kilograms of longan, so the price of 10 kilograms of lychee is equal to the price of 4 kilograms of longan.

Lychee = yuan kilogram.

Longan = 78 4 = yuan kg.

5 From A to B, a telephone pole was originally installed every 45 meters, plus two poles at both ends, a total of 65 electric poles, but now it is changed to install a telephone pole every 60 meters.

Distance=45*(65-1)= 2880 meters.

60 meters of installation = 2880 60 = 48 roots except for both ends to install 47 roots.

180 meters, 360 meters Telephone poles with integer multiples of 180 do not have to be moved.

Altogether 2880 180-1 = 15 poles do not have to move.

6. The two cars of A and B drove opposite each other from the two stations of AB at the same time, and met for the first time at a distance of 90 kilometers from station A. After the encounter, the two cars continued to move at the same speed, and returned immediately after reaching the destination, and the second meeting was 50 kilometers away from station A. Find the distance between two stations?

A-90 B-90

A L-90 + L-50 B 90 + 50

90：l-90 = （2l-140）：140

l-90）（2l-140）=140*90

2l^2-320l=0

l = 160 km.

A105 B70

1 car for 29 people and 2 cars for 29 people.

3.Number 96, Language 92, English 88

4.Since the price of 5 kg of lychee is equal to the price of 2 kg of longan, 4 kg of longan = 10 kg of lychee.

It is the ** longan of the lychee =

5.There are 11 more that don't move.

The answers should be more detailed, I hope it can help you.

(1) Set the highest score to x points and the lowest score to score y.

x+y=158

x=5/3y-2

Solution x = 98 points.

y=60 points.

The maximum score is 98 and the lowest score is 60.

3) Let the velocity of A be x, then the velocity of B is x+3x+3 (x+

x = the velocity of A is then the velocity of B is 4 km h

4) Set up x people from team B to team A.

196-x=1/3(272+x)

x = 79.

79 people should be transferred from Team B to Team A.

1, and times the problem.

And: 158 + 2 160

Times: 1 and 2/3 5 3

Minimum score: 160 (5 3+1)=60

Maximum score: 158 60 98

2，a+b=13

2(10a+b)-4=10b+a

8b=19a-4

8b=104-8a

108=27a

a=4b=9

This two-digit number is 49

3, speed and 24 3 = 8

Speed difference A speed: (

B Speed: (8+.)

4, and: 272+196 468

Multiple: 3 Team B: 468 (3+1)=117

196 117 79 people need to be transferred to Team A.

1. Assuming that the highest score is x and the lowest score is y, then 5 3y-2+y=158 y=60 x=98

4. Assuming x people are transferred from team B, then 196-x=1 3(272+x) x=79

3. Assuming a velocity x, then 3x+3*( x=2, assuming that the ten digits are x, the single digit is y, x+y=13 yx=2xy-4 then x=4 y=9 that is, the two-digit number is 49

1. Let the lowest score be x and the highest score be y.

y=x*(5/3)-2

x+y=158

The solution yields {x=60

y=98

1 98 and 60 points.

3 A kilometre per hour, B kilometre per hour.

If the original x tons of warehouse B are set, then A has 12x 11 tons, then 12x 11=(x-24)(1+1 5).

12x/11=6(x-24)/5

x = 264, that is, warehouse B originally had 264 tons of grain.

Solution: Because tan abo=1 2,ob=4,oe=2, so ce=1 2eb=1 2*6=3, so the coordinates of point c are (-2,3), and the coordinates of point b are (4,0), let the inverse proportional function analytic formula be y=k x, substitute the coordinates of point c to get y=-6 x, let the analytical formula of the primary function be y=kx+b, and substitute the coordinates of a and b to get y=-1 2x+2.

The simultaneous equation of the two functions gives x1=6,x2=-2, so the coordinates of point d are (6,-1), so s cod=1 2*ob*ce+1 2*ob*1=1 2*4*3+1 2*4*1=6+2=8