113 faces (1-6) The track of the sports ground is 400m long. A practices cycling, with an average of 350m per minute; B practices running, with an average of 250m per minute. How long has it taken for the two people to meet for the first time from the same place and in the opposite direction at the same time? How much time did it take to meet again?

113 faces (1-6) The track of the sports ground is 400m long. A practices cycling, with an average of 350m per minute; B practices running, with an average of 250m per minute. How long has it taken for the two people to meet for the first time from the same place and in the opposite direction at the same time? How much time did it take to meet again?

400 / (350 + 250) = 0.8fen = 48S 2. Or 48S

In order to make more profits, a candy store decided to pack the new 60kg bulk milk candy before selling it. There are two kinds of packing boxes of 3kg and 2kg, and the cost of each box is 0.8 yuan and 0.6 yuan respectively. (1) if all of them are packed in 3kg, the total cost of packing box is 0.8 yuan______ Yuan; if all packed in 2kg, the total cost of packing box is required______ (2) if considering the customer's demand, the store requires that the quantity of milk candy in 2kg package is not less than 20kg, how to design the packaging scheme to save the cost of the packaging box most? What is the most cost saving? (ask for reasons)

(1) (2) suppose that there are x and Y boxes in 3kg and 2kg respectively, and the total cost is w yuan. Then the solution of 3x + 2Y = 60W = 0.8x + 0.6y shows that w = 16 + 115y is y ≥ 10 and x = 20-23y because 2Y ≥ 20, and X and y are positive integers. If the cost is the minimum, then x = 12 when y = 12, and w = 16.8

Simple questions on Mathematics in grade one~~~
*Take advantage of
Observe the following equation:
2=2=1*2；2+4=6=2*3；2+4+6=12=3*4；2+4+6+8=20=4*5……
(1) We can guess what is the sum of N consecutive even numbers starting from 2?
(2) When n = 10, what is the sum of 10 consecutive even numbers starting from 2?

n*(n+1)
10*11=110

If we know that x is an integer and 2x + 3 + 23 − x + 2x + 18x2 − 9 is an integer, then x is ()
A. 2 b. 3 C. 4 d. 5

The original formula = 2 (x − 3) − 2 (x + 3) + 2x + 18 (x + 3) (x − 3) = 2 (x + 3) (x + 3) (x − 3) = 2x − 3, when x-3 = 2, i.e. x = 5, the original formula value is an integer; when x-3 = 1, i.e. x = 4, the original formula value is an integer; when x-3 = - 1, i.e. x = 2, the original formula value is an integer; when x-3 = - 2, i.e. x = 1, the original formula value is an integer, the symbol

If the power 0 of the algebraic formula (X-2) + the power - 2 of (y + 1) is meaningful, then the value range of X and Y is

X ≠ 2, and Y is not equal to - 1

Given the function f (x) = x2 + ax + A, (1) when a = 4, the inequality f (x) > 16 is solved
Given the function f (x) = x2 + ax + A, (1) when a = 4, solve the inequality f (x) > 16 (2) if f (x) > = 1 holds for any x, find the value of real number a

(1) Given the function f (x) = x2 + ax + A, (1) when a = 4, solve the inequality f (x) > 16 A = 4, f (x) = x ^ 2 + 4x + 4x ^ 2 + 4x + 4 > 16x ^ 2 + 4x-12 > 0 (x + 6) (X-2) > 0, and get the solution of X2 (2) x ^ 2 + ax + a > = 1 x ^ 2 + ax + (A-1) > = 0, and the discriminant △ = a ^ 2-4a + 4

Given the point m (3,1) straight line L: ax-y + 4 = 0, circle (x-1) square + (Y-2) square = 4, we can find the tangent equation of the circle m, if we find a at the intersection of line L and circle AB2 point | ab | = 2 ∫ 3

(1) The point m is tangent to the circle, which means that there is only one intersection point between the line and the circle, that is, the equation of the circle and the equation of the line have only one unique solution, that is △ = 0. Suppose that the equation of the line passing through the point m is y = KX + B, then the coordinates of the point m will be brought in: 1 = 3K + B ∧ B = 1-3k ∧ the equation of the line passing through the point m is y = kx-3k + 1

There is 3000 R / kW · h on the surface of the electric energy meter. If the electric energy meter is powered on for 10 minutes and the rotary table of the electric energy meter turns 50 turns, what is the work done by the current?

It means to use 1 degree of electricity per 3000 revolutions, that is 3.6 * 10 ^ 6 joules
50 laps is 6 * 10 ^ 4 joules
It has nothing to do with time

Math problem (I'm too lazy to do it)
There are 290 students in grade 4 going to spring outing. How many carts and cars are suitable? How much is the minimum?
800 yuan for 42 people
Car seat 19 people 380 yuan

290÷42=6``````38
38÷19=2
Answer: 2 minibuses and 6 buses

The name plate of electric kettle is: rated power 220 V, frequency 50 Hz, rated power 1000 W, capacity 1.0
The name plate of electric kettle is: rated power 220 V, frequency 50 Hz, rated power 1000 W, capacity 1.0 L, the resistance of electric kettle is calculated

The thermal resistance of the electric kettle is 48.4 Ω, which is much smaller in the cold state (the resistance wire is a positive temperature coefficient, which is small in the cold state and 48.4 Ω in the high temperature)
It can be calculated according to the formula given by netizens