Mr. Zhang and Mr. Li start from school at the same time, and walk to the county to buy books. Mr. Zhang is younger than Mr. Li every day At the same time, Mr. Zhang and Mr. Li set out from school and walked to the county town to buy books. Mr. Zhang walked 1km more per hour than Mr. Li, and the time that Mr. Zhang spent less than Mr. Li was just one sixth of the total walking time. How many kilometers each of the two teachers walked per hour Please give me a specific solution. Thank you Only one unknown number is set

Mr. Zhang and Mr. Li start from school at the same time, and walk to the county to buy books. Mr. Zhang is younger than Mr. Li every day At the same time, Mr. Zhang and Mr. Li set out from school and walked to the county town to buy books. Mr. Zhang walked 1km more per hour than Mr. Li, and the time that Mr. Zhang spent less than Mr. Li was just one sixth of the total walking time. How many kilometers each of the two teachers walked per hour Please give me a specific solution. Thank you Only one unknown number is set

Let Mr. Li walk x km per hour, then Mr. Zhang walk x + 1 km per hour, x = (x + 1) * 5 / 6, x = 5, so Mr. Li walk 5 km per hour, Mr. Zhang walk 6 km per hour

Mr. Zhang and Mr. Li set out from school at the same time, walking 15 kilometers to buy books in the county
As a result, Mr. Zhang arrived half an hour earlier than Mr. Li. How many kilometers did the two teachers walk each hour

15÷x－15÷（x＋1）＝0.5
x²＋x－30＝0
（x＋6）（x－5）＝0
X1 = 5, X2 = - 6
X + 1 = 5 + 1 = 6 km / h Mr. Zhang's speed

Please use the surrogate elimination method to solve the following equations:
(1)9s-13t+12=0 (2)x/4+y/3=4/3
s=2-3t 3(x-1)=4(y+2)
1)9s-13t+12=0 s=2-3t (2)x/4+y/3=4/3 3(x-1)=4(y+2)
The format is wrong. It should be like this

9s-13t + 12 = 0, s = 2-3T, substitute s into 9 (2-3T) - 13T + 12 = 0 → 18-27t-13t + 12 = 0 → 30 = 40t → t = 3 / 4
X / 4 + Y / 3 = 4 / 3 → 3x + 4Y = 16 → y = 4-16 / 3x is substituted by 3 (x-1) = 4 (y + 2) to get x = 27 / 19y = - 68 / 19

If a1 + A5 = 2, A3 + A7 = 6, then A5 + A9

1. 3500mm = () L2, 1.2L = () cm3, 6.25m2 = () m2 = () DM2

1. 3500 ml = (3.5) l
2. 1.2 L = (1200) CC
3. 6.25 square meters = (6) square meters (25) square decimeters
If you have any questions, please ask,

A local product company organized 20 vehicles to transport 120 tons of a, B and C local products to other places for sale
(local products a B C) carrying capacity of each vehicle (ton) 8 65
Profit per ton of local products (100 yuan) 12 16 10
(1) Let X be the number of vehicles carrying a local specialty, and y be the number of vehicles carrying B local specialty
(2) If there are no less than 3 vehicles for each kind of local products, then there are several vehicle arrangements and write down each arrangement
(3) In order to maximize the profit of this sale, which arrangement should be adopted in (2) and the value of maximum profit should be calculated

（1）8x+6y+5（20―x―y）=12 0
The functional relation between Y and X is y = 20 ― 3x
(2) From X ≥ 3, y = 20-3x ≥ 3, 20-x - (20-3x) ≥ 3, we can get
And ∵ x is a positive integer ∵ x = 3,4,5
Therefore, there are three schemes for vehicle arrangement, as follows
Scheme 1: 3 A, 11 b and 6 C
Scheme 2: 4 vehicles of type A, 8 vehicles of type B and 8 vehicles of type C
Scheme 3: 5 A, 5 B and 10 C
(3) Suppose the sales profit is w yuan,
W=8x·12+6（20－3x）·16+5[20－x－（20－3x）]·10=－92x+1920
∵ w decreases with the increase of X, and then x = 3,4,5
When x = 3, Wmax = 1644 (hundred yuan) = 164400 yuan
A: in order to make the biggest profit from this sale, we should adopt the first scheme in (2), that is, 3 vehicles of type A, 11 vehicles of type B and 6 vehicles of type C. The maximum profit is 164400 yuan

How many tons is a cubic stone

See the specific density:
dry
8 tons / m3, then one cubic meter
It is equal to 1.8 tons
If the density of dry sand is 1.20-1.65 T / m3, then one m3
Equal to 1.20 tons - 1.65 tons

How to solve 5x-20 * 5 = 2.5x 20

x+10=2.5x-20
2.5x-x=10+20
1.5x=30
x=20

Cut an 8-decimeter-high cylinder into an approximate cuboid. The surface area is increased by 48 square decimeters. What is the volume of the cylinder?

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The radius is:
48 / 2 / 8 = 3 (decimeter)
Bottom area:
3.14 × 3 × 3 = 28.26 (square decimeter)
The volume is:
28.26 × 8 = 226.08 (cubic decimeter)

2 / 3 of a number is equal to 5 / 7 of 28. What is the number
What is the quotient of the difference between 4 / 3 and 1 / 2 divided by the sum of 2 / 3 and 5 / 6

28*(5/7)=20,20/(2/3)=30
(4/3-1/2)/(2/3+5/6)=(8/6-3/6)/(4/6+5/6)=(5/6)/(9/6)=5/9