Solving practical problems with equations A shop sells two pieces of clothes. For some reason, the one with lower purchase price loses 10 yuan, and the one with higher purchase price makes at least 20% profit, so that the two pieces of clothes will not lose money. What is the purchase price of the one with higher purchase price?

Solving practical problems with equations A shop sells two pieces of clothes. For some reason, the one with lower purchase price loses 10 yuan, and the one with higher purchase price makes at least 20% profit, so that the two pieces of clothes will not lose money. What is the purchase price of the one with higher purchase price?

Let the dress with higher price be x yuan
x*20%=10
The solution is x = 50
A: the purchase price of this dress with higher purchase price is 50 yuan

In the face of all kinds of application problems of one variable linear equation, how to make equations? Please give examples to illustrate all the problems in Volume 1 of grade 1 and 7 of junior high school,
When a ship goes against the water for X / h, it can still make a profit of 10% with a price of XXX and 50% discount

When you don't know how to make a trip, draw a picture. It's easier to understand. 1. A and B leave at the middle point of a and B's journey in the opposite direction at the same time. After 6 hours, a arrives at city a, and B is 60 kilometers away from city B. the speed ratio of a and B is 4:3. Find the distance between city ab

In the first quarter, the electricity fee of a factory was a yuan, and the water fee was 40 yuan more than twice the electricity fee. In the second quarter, the electricity fee was saved by 15%, and the water fee was 38% more
Compared with the first quarter, the water and electricity cost of the factory in the second quarter is overspended or saved? How much is overspended or saved? It will be paid tomorrow

In the first quarter, the water charge is more than two times of the electricity charge, 40 yuan. It can be seen that the water charge is 2a-40, and the water and electricity charge in the first quarter is 3A + 40
In the second quarter, we saved 15% of the electricity charge, which shows that the electricity charge in the second quarter is a multiplied by (1-0.15) = 0.85a
38% more water fee in the second quarter: the electricity fee in the second quarter is the water fee in the first quarter multiplied by (1 + 0.38) = 2.76a + 55.2
Therefore, the water and electricity cost in the second quarter is 0.85a + 2.76a + 55.2 = 3.61a + 55.2
Second quarter water and electricity fee - first quarter water and electricity fee = 0.61a + 15.2
Since the water and electricity charges are positive, a is greater than 20
That is, the second quarter is 0.61a + 15.2 yuan more than the first quarter

The distance between a and B is 360 km. The passenger cars and freight cars start from place a to place B at the same time. The speed of the freight cars is 60 km / h, and the speed of the passenger cars is 40 km / h. after arriving at place B, the freight cars stop for half an hour, and then return to place a at the same speed______ The two cars met in two hours

The truck stops for half an hour after starting from a place and arriving at B place. The shared time is: 360 △ 60 + 0.5 = 6.5 (hours) (360-40 × 6.5) △ 60 + 40 = (360-260) △ 100 = 100 △ 100 = 1 (hours), 6.5 + 1 = 7.5 (hours). Answer: the two cars meet 7.5 hours after starting from a place. So the answer is: 7.5

Simplification: 1 / 1 × 4 + 1 / 4 × 7 + 1 / 7 × 10 + ＋1／（3n-2）×（3n+1)

1／1×4 ＋ 1／4×7 ＋ 1／7×10 ＋…… ＋1／（3n-2）×（3n+1)
=1/3(1-1/4+1/4-1/7+.+1/(3n-2)-1/(3n+1))
=1/3(1-1/(3n+1))
=1/3*3n/(3n+1)
=n/(3n+1)

Cheetah is the fastest animal on land. It runs about 30 meters per second, 11 / 20 faster than a car. How many meters does a car run per second?

30÷(1-11/20)

The cube of any natural number is equal to the sum of consecutive odd numbers
I've only learned if while for these
How to write is easier to understand~
Verify the above conclusion: for example, 1 ^ 3 = 1; 2 ^ 3 = 3 + 5; 3 ^ 3 = 7 + 9 + 11
Requirements: the program calculates and outputs the corresponding continuous odd number for each input natural number
Don't be difficult. I can only use the simple while for if level~

I don't know if the owner has noticed:
1^3=1^2-0^2=(1-0)*(1+0)=1*1;
2^3=3^2-1^2=(3-1)*(3+1)=2*4;
3^3=6^2-3^2=(6-3）*（6+3）=3*9；
So I just need to find out the two factors A and B of the same sign of the natural number you input
Then use X-Y = a; X + y = B; to find x, y
The procedure is as follows:
#include
#include
int main()
{
int n;
scanf("%d",&n);
int data=(int)sqrt(n);
int a,b,x,y,i,j;
for(i=1;i

How to arrange the size of the sun, universe, galaxy, moon and earth?

Big to small: universe, galaxy, solar system
Solar system: the sun is larger than the earth and the moon

Solve the equation: 1 / X (x + 2) + 1 / (x + 2) (x + 4) + +1/(x+8)(x+10)=5/24

1/x(x+2)+1/(x+2)(x+4)+…… +1/(x+8)(x+10)=5/241/(2x)-1/{2(x+2)) + 1/{2(x+2)}-1/{2(x+4)} +…… +1/{2(x+8)} - 1/{2(x+10)} = 5/241/(2x)-1/{2(x+10)} = 5/241/x-1/(x+10) = 5/1210/{x(x+10)} = 5/122/{x(x+10)} =...

Why there must be elasticity when there is friction
Is it not that there is no elasticity in motion? The relationship between elasticity and sliding friction, static friction? The diagram of elasticity? Elasticity and motion?

As long as there is contact and extrusion (deformation), there is elasticity
Elasticity is the premise of friction
The direction and magnitude of the elastic force can be judged according to the balance of the force or the deformation direction of the object (opposite)
There should be no direct relationship between elasticity and exercise
You can take a look at the relevant materials of senior one physics to learn this aspect