The title is as follows: There are 55 dimes of one dime, two dimes and five dimes, which are worth 10 yuan. If the number of Dimes is the same as that of two dimes, how many of them are there? Oh, my God. That's a tough question (if you can, please make a simple equation or formula.) 0.1X+0.2X+(55-2X)*0.5=10 Is this x really 25?

The title is as follows: There are 55 dimes of one dime, two dimes and five dimes, which are worth 10 yuan. If the number of Dimes is the same as that of two dimes, how many of them are there? Oh, my God. That's a tough question (if you can, please make a simple equation or formula.) 0.1X+0.2X+(55-2X)*0.5=10 Is this x really 25?

Suppose there are x in one corner, then there are x in two corners and 55-2x in five corners
0.1*X+0.2*X+0.5*(55-2X)=10
(0.1+0.2)X+27.5-X=10
0.3X+27.5-X=10
27.5-10=X-0.3X
17.5=0.7X
X=25
55-2X=55-25*2=5
So there are 25 in one corner, 25 in two, and 5 in five

A class of natural numbers whose sum of digits is 2003, then the smallest of these natural numbers is______ ．

2003÷9=222… The smallest of these natural numbers is 599 The answer is: 599 9 (222 9)

If cos α = sin α, then the range of the terminal edge of angle α in the first quadrant is ()
A、（0,π/4]
B、[π/4,π/2）
C、[2kπ+π/4,2kπ+π/2],k∈Z
D、（2kπ,2kπ+π/4],k∈Z

Choose C, [2K π + π / 4, 2K π + π / 2], K ∈ Z
Because cos α = sin α, so π / 4

A batch of cement is needed at the construction site. 240 bags are transported in the first time, and the remaining 5 / 7 bags are still 80 bags. How many bags are there?

The remaining 5 / 7 of the second shipment left 80 bags = the remaining 2 / 7
So: the rest = 80 / (2 / 7) = 280
280+240=520

If the sides of △ ABC are all integers and the length of the largest side is 7, then such triangles have the same length______ One

Let the other two sides be x, y, then x ≤ 7, y ≤ 7, and X + Y > 7, and X, y are all integers. Let x ≤ y, the values of X, y satisfying the above conditions are: 1, 7; 2, 6; 3, 5; 4, 4; 6, 3; 2, 7; 4, 5; 4, 6; 5, 5; 7, 3; 4, 7; 5, 6; 5, 7; 6, 6, 7; 7, 7

How many tons is the weight of sand stone?
Please help me. If you know the reply, please send it to me

The density of rocks varies greatly, and there are many influencing factors. It's not clear what kind of rock you mean! But the density of rocks in general engineering is calculated according to 2.5. Here are some rock density data, which I reprinted: Granite: 2.63 ~ 3.3, syenite: 2.3.3, diorite: 2.3.3, porphyry: 2.8, andesite: 2

The sum of coefficients of odd power of X in the expansion of (1 + X + x ^ 2 + x ^ 3) ^ 4

When x = 1, (1 + X + x ^ 2 + x ^ 3) ^ 4 = 256
When x = - 1, (1 + X + x ^ 2 + x ^ 3) ^ 4 = 0
The left side of the subtraction is exactly twice the sum of the coefficients of the odd power of X, and the right side is 256
So the sum of coefficients of odd power of X is 256 / 2 = 128

There were 56 students in Grade 6, of whom 4 / 7 were boys. Later, there were some girls. The ratio of boys to girls was 16:13. Now how many students are there in the class

Set the number of transferred girls as X
Before, there were 32 boys and 24 girls
Then the formula 32: (24 + x) = 16:13
The solution is: x = 2
There are 56 + 2 = 58 students in the class

Y = - X-1 y = - 2 / X for XY
Solving equations

y=-x-1
y=-2/x
-x-1=-2/x
x²+x-2=0
(x+2)(x-1)=0
x1=-2,y1=1
x2=1,y2=-2

During the world table tennis championships, at a gathering of athletes from all over the world, there are three pairs of mixed doubles players sitting together. They are x, y, Z three male players and a, B, C three female players. Among them, the partner of player X and the partner of player C, the partner of player B and player a meet for the first time. When player Z knows all the people, the partner of player a is______ ．

It's the first time that player X's partner and player C's partner, player B's partner and player a meet. It's concluded that neither player C nor player B's partner is Z. because Z knows everyone, Z's partner is only a. A: player a's partner is Z. so the answer is: Z