Math questions, please elaborate, I will have extra extra points

Let's break it down:

First of all, only 4 games, A is excluded;

Because B loses all and C only wins one, so C can only win B, so E wins at least 2 games, and C is excluded;

A won B, C, and the rest were all lost, so C won 3 games, and D won all, so C lost 1 game, and D3 won 1 loss.

d set x wins, y loses, according to total wins = total losses.

x+2+0+1+4=y+2+4+3+0, so x-y=2, known to have played 4 games, x+y=4, just solve the system of equations, x=3, y=1

Pick D, because every game played, there is always a winning and losing side, so the number of wins and losses is the same, so add up the wins and losses of ABCD 4 Middle School: 7 wins and 9 losses. Then E Middle School has 3 wins and 1 loss.

You may ask, why not 4-2 or 2-0 and so on?

This is to count the total number of their games: "Each middle school played one game against each other, and they played a single round-robin match", A played 4 games, B because the games between A and B have been counted in the calculation of A, so B is 3, and C is 2, D is 1, and E is 0; 4+3+2+1=10。So the total wins and total losses are both 10.

1) By |a+b|=-a-b is a negative number for a+b, and |a|=8,|b|=4, then a=-8, b=-4, or a=-8, b=4, then a+b=-12 or -4

2) a, for example, a=1, b=2, c=-5, a+b+c=-2<0 - > three numbers are two positive and one negative;

a=1,b=-2,c=-5,a+b+c=-6<0 - > three numbers are one positive and two negative;

a=-1,b=-2,c=-5,a+b+c=-8<0 - > three numbers are three negatives;

Therefore, c is the correct solution.

216 18 = 1200 yuan.

The total expenditure in May was $1,200.

Solution: Let the total expenditure be x

18%x=216

Solution x=1200

Medical: 1-10%-18%-24%-36%=12%1200x12%=224 yuan.

216 18 = 1200 yuan.

The total expenditure in May is 1200 yuan, which can also be set to x 18% x = 216

And why not 100 percent?

1, Bei Bei and Huanhuan started at the same point on the 400-meter circular runway, Bei Bei ran 4 meters per second, and Huanhuan ran 6 meters per second. How long after the two of them first met?

Solution: This question has a review note, starting from the same point, I don't know whether it is in the same direction or in the opposite direction, and it is answered in two meanings.

Pursuit problem in the same direction 400 (6-4) = 200 seconds.

Reverse is an encounter problem: 400 (4+6)=40 seconds.

A: If you run in the same direction, it will take 200 seconds to catch up with the encounter, and if you run in the opposite direction, it will only take 40 seconds to meet.

2. It is necessary to use 10 trucks of two types A and B to transport 68 tons of goods from the terminal, each type A truck can transport 8 tons, and each type B truck can transport 4 tons. How should A and B trucks be deployed?

Untie; The chickens and rabbits are in the same cage, assuming that all of them are loaded into the A-type truck, then the B-type truck has.

Assuming that all are loaded into the B type truck, then the A type truck has.

A: Choose 3 Type B cars and 7 Type A cars.

3. There are only 25 multiple-choice questions in one test paper, 4 points are awarded for doing one question correctly, and one point will be deducted for doing wrong or not answering. A student scored 90 points, how many questions did he get right?

Solution: The problem of chickens and rabbits in the same cage.

4 points are awarded for doing a question correctly, and a question is equivalent to 4+1=5 points less.

Assuming that all are done right, then there are those who are wrong.

Get it right 25-2=23

Answer: I got 23 questions right.

The first encounter, that is, when Huanhuan ran one lap more than Bei Bei and caught up with Bei Bei, so = 400 (6-4) = 200s

Let a have x, and b is 10-x

A can carry a total of 8x, and B can carry a total of 40-4x

So 8x+40-4x=68

x=7，10-7=3

There are a total of 25 questions, four points for correctness, so it is 100 points for all of them, and one point is deducted for making mistakes or not answering, so it is -5 points, and 90 points are obtained, so there are 2 wrong or unanswered questions, that is, 23 questions are correct.

The answer to the first question is 24 meters because 24 is the least common multiple of 4 and 6.

The answer to the second question is 8 A cars, and one B car is the most reasonable.

The third question is 25 4 = 100 points 100-90 = 10 points 4 + 1 = 5 points 10 5 = 2 questions 25-2 = 23 questions.

The answer is 23 questions to get right.

To be honest, I will only do the third question: 4 points for doing a question correctly, and if you make a mistake and you can't get 4 points, it is actually 4 + 1 = 5 points.

Assuming all of them are answered correctly.

25x4-90) divided by (4+1)=2 (question) is a typo, 25-2=23 (question).

The number of parts of the sum of the length and width of the rectangle 3 2 = 5 parts.

The number of parts of the sum of the length and width of the rectangle 7 5 = 12 parts.

The least common multiple of 5 and 12 is 5 12=60 parts.

Therefore, A is 60 3 5=36 wide 60 2 5=24 B is 60 7 12=35 wide 60 5 12=25, so the ratio of the area of A and B rectangles is (36 24):(35 25)=864:875

A is long x and wide is x*2 3, B is long y and wide is y*5 7

2*(x+x*2/3)=2*(y+y*5/7)

Get x y=36 35

It's the area ratio, right? The ratio of area is 864:875

3:2=36:24, 7:5=35:25

36 + 24 = 35 + 25, the circumference of the two rectangles of A and B is equal, so the area ratio is 36 * 24 35 * 25 = 864 875