Fengtai No. 12 Middle School 2009 Primary School Sixth Grade Mathematics Olympiad Questions? Urgent!

Let A be x, B be y, C be z, 4x=3y, y=4 3x, 4y=5z, y=5 4z, 4 3x=5 4z, 16x=15z, so x=15, z=16, y=20 so A is 15, B is 20, and C is 16

9th, 1-2 3-1 4=1 12, so there are 12 people in total, and there are 8 in front of him.

RPS ratio A: B 4:3 16:12

B: C 4:5 12:15

A:B:C 16:12:15

The number of teeth ratio A: B: C 1 16:1 12:1 15 15:20:16 The number of teeth of B wheel is: 2 (16-15) 20 40

1: 14 hours and 20 minutes.

2: 20% off.

4:5: 17 units.

6:92.

7: 130 meters.

8: 320 blocks.

Another 1 to 3 hours.

Fold (, x=and 450 units. Piece.

Rice. Yuan This is the answer, the result has to be pushed slowly, in fact, it is quite easy.

Another 1 to 3 hours.

Fold (, x=and 450 units. Piece.

Rice.

1) 14 hours and 20 minutes.

2) 4% off.

3) Grade 5: 270, Grade 6: 450

6) 8/8 out of 88.

Another 1 3 hours that is 14 hours and 20 minutes fold (,x=

and 450 units. Piece. Rice.

1. It took X hours to complete the task.

1/12*x/2+1/18*x/2=1

x = A: Hours were shared to complete the task.

1) 14 hours and 20 minutes.

2) The remainder is calculated at 20% of the profit 4% off??

3) Grade 5: 270, Grade 6: 450

6) 8/8 out of 88.

A is 25% of B number, 20% of C is counted, and A is 10% of C number?

What is the expected profit when pricing a 20% discount on a product** and still making a 20% profit?

A washing machine to carry out price reduction activities, if the current price is reduced by 10%, you can get a profit of 180 yuan, if the price is reduced by 20%, then the loss of 240 yuan, how much is the purchase price of this washing machine?

There are turtles and cranes in the zoo, and there are 14 more cranes than turtles, and 18 more cranes have feet than turtles.

Is this called the Olympiad? For the first year of junior high school, it is pediatric, time is limited, look at the answers upstairs.

1、（4-1）÷（3-2）=3

The original number is 3 5

2. If the numerator is added to 1, this fraction is equal to two-fifths, indicating that the numerator is less than 1 from the denominator of 2 5 If the denominator is subtracted from 4, this fraction is equal to one-half, indicating that the numerator is less than 1 2 less than the denominator, so (2-1) (1 2-2 5) = 10

The original number is 3 10

Set the amount of milk in the cup to 1

After drinking 20%, fill up with water, and the amount of milk at this time is 80%.

Drink another 40%, then fill up with water, this time drink the milk, the remaining milk, so it accounts for 48%.

If there are x white balls, then there are (3x+2) red balls.

In addition, a total of t times were taken from the ball, that is, 7t white balls and 15t red balls were taken.

Then according to the title, there is a system of equations.

3x+2-15t=53

x-7t=3

Solve the system of equations and get t=7, x=52

There are 52 white balls, and there are 3*52+2=158 red balls 158-52=106 more red balls than white balls.

Therefore, there were 106 more red balls than white balls in the box.

Set up singles group x group, then the doubles group has (x-13) group, then the number of singles is 2x, and the number of doubles is 4 (x-13) according to the meaning of the question, the equation 2x-4(x-13)=16 is sorted out, and 52-2x=16 is obtained

Solve the equation to get x=18

2x=2*18=36 (person), 4(x-13)=4*(18-13)=20 (person).

So, there are 36 in singles and 20 in doubles.

If you take 7 white balls and 21 red balls from the box, take them like this every time, and the number of red balls taken out is three times that of the white balls, so that in the box, the number of red balls is always kept at 3 times the number of white balls, more than 2 Note, for the above method and the method in the question, if the number of times is the same, the number of white balls in the box is the same, so if there are 3 white balls left, there should be 11 red balls left (3 times more than 2), but in fact there are 53 red balls left, The difference in the result is 42, which is caused by taking 21-15 = 6 more each time, so it can be seen that a total of 42 6 = 7 times are taken, so the number of white balls: 7x7 + 3 = 52 red balls: 52x3 + 2 = 158

The first one: a system of 3 yuan 1st order equations, let: white has the original x, red y, the order is n, (1) y=3x+5(2) x=3+7n(3) y=56+15n, and the solution gives x=52 y=161, that is, the number of red balls.

n=7Second: Let doubles x+16 (x+16) 2=x 4+13x=20

（100-48）/（1+3/10)=40

100-40 = 60 for basketball

Solution: If there are x people in the first grade, then there are (300-x) people in the second grade according to the question:

2/5x-1/4(300-x)=55

8x-5(300-x)=1100

13x=2600

x = 200 Answer: 200 in the first grade and 100 in the second grade.

(1)(5/4)*(6/5)]/(5/6)=9/5(2)3-=3/5

3) (will not).

4) (will not).

5) (will not).

6) How can two cruise ships depart from the same place at the same time, one going down the river and the other upstream???