Simple Olympiad questions are in! Speed, Math Olympiad, Speed!

Suppose there are x boys, then there are (152-x) girls.

The current boys have (10x) 11

Now there are 152-x-5 girls

The two are equal, and the equation (10x) 11=152-x-5 can be solved to get x=77

So there are 77 boys and 75 girls.

Set 11 boys x Y girls

11x+y=152

11x*(1-1/11)=y-5

Solution. x=7

y=75, so 7*11=77 for men and 75 for girls.

Let the boy be x and the girl be y x+y=152 x-x(1 11)=y-5 to solve the equation.

Column equations: let male x person, female y person.

10/11x=y-5

x+y=152

x=77,y=75

I'm unique, I can solve it without equations. If the boy is regarded as the whole "1", then "the boy is gone 1 11!" 5 women are gone, and as many are left", that is, 1-1 11 = 10 11 each, and 152-5 = 147 corresponds to a fraction of 1 + 10 11 = 21 11, so the number of boys is 147 (21 11) = 77 and the number of girls is 152-77 = 75.

A: 77 males and 75 females.

Set to open x inlet pipes, y hours.

3*10=xy+3x

6*6=xy+6x

3x=6x=2y=12

Then set at least a pipe.

10*a=xy+10x

10a=24+20

a=So open at least 5 drains.

Let's say the drain drains 1 per hour

The hourly water inflow is (6*6-10*3) (6-3)=2, and the amount of water discharged before drainage is 6*6-6*2=24

Therefore, if you want to empty the pool in 10 hours, you must open at least the number of drains (24+10*2) 10=roots, that is, 5 roots.

First, open the inlet pipe to fill the pool with more water A, and fill the pool with 10 inlet pipes in B hours. Each drain pipe drains c per hour, and at least x drains should be opened.

a=3（10/c-1/b) (1)

a=6（6/c-1/b) (2)

a=10（x/c-1/b) (3)

1), (2) Coupling.

3（10/c-1/b)=6（6/c-1/b)c=2b

Substituting (2)a=12 b

Substituting (3) 12 b = 10 (x 2b - 1 b).

x = So, open at least 5 drains.

a=6*2/a

Solution: If x square meters are demolished, then a new (4x+2000) square meter will be built, 20000-x+(4x+2000)=20000(1+40%)x=2000

So 2,000 square meters were demolished and 10,000 square meters were newly built.

Hope it helps!

If you set up to demolish x, then build a new 4x+2000

The equation is 20000-x+4x+2000=20000+20000*40%.

The solution yields x=2000

Demolish 2000, build 10000

a=1 to the power of 2013 (-2013) (-2013).

1 2013 2013) 2013b = (-10) to the 9th power (-13) to the 10th power (-130) to the 9th power.

10 13 1 130) to the power of 13

So a-b = 2013-13 = 2000

The length of the side of the square is considered to be 1, then the original length is 1 (1-1 7) = 7 6, and the original magnanimity is 1 (1 + 1 5) = 5 6

The width of the original rectangular shirt is 5 6 (7 6) = 5 7

Suppose the student has x hours to pick things up and back.

5+5x= (both ends of the equation represent the distance from the school to the team) x=45+5 4+

A: The distance from the school to the zoo is kilometers.

Solution: The distance from the school to the zoo is X kilometers.

Solve the equation and get: x=

To the left and right of the equal sign is the time it took for the student and the team to meet each other.

Solution: Suppose the student has x hours to pick things up and back.

5+5x=x=25+5×2+

A: The distance from the school to the zoo is kilometers.

From the meaning of the title, it can be seen that [(n 2-1) 2-1] 2-1=1 solves n = 22, 22 apples are six yuan six, and one apple is three cents.

The answer is 3 corners.

The single digit 3 is incorrectly written as 8, that is, there are 5 more, to be subtracted, and the ten digit 0 is incorrectly written as 6, that is, there are 60 more, to be subtracted, so the final result is 199-5-60=134

The first problem does not solve the equation:

After C has been taken, it is 1, then before C has gone, it is (1+1)*2=4, and before B has been taken, it is (4+1)*2=10.

Then before A, it is (10+1)*2=22.

1. Because there is one apple left, it is restored, before C is taken: (1 + 1) * 2 = 4 (pieces) B before it is taken: (4 + 1) * 2 = 10 (pieces) A is taken before: (10 + 1) * 2 = 22 (pieces).

A total of 22 apples.

Yuan) A: The average yuan per apple.

2. The subtracted single digit 3 is mistakenly written as 8, 5 more, and the ten digit 0 is mistakenly written as 6, and there is 60 more, so:

199 is 65 more than the original, 199-65 = 134

A: The correct answer to this question is 134.

Question 1: After taking C, there is one left, and before you take it, there are 4.

B takes the remaining four, and before he takes it, it's 10.

A has 10 left, and before he takes it, it's 22, get it, and the second question Suppose that the correct answer is x

Only a single digit 3 is written as 8, which is equivalent to x+5=199, and only ten digits 0 is written as 6, which is equivalent to x+60=199, so it is written incorrectly, which is equivalent to 199-5-60=x, so x is equal to 134

After opening the door, the number of people who come every minute (10*4*20-400) 20=20 (Juchang people).

Open 6 entrances 400 (10*6-20) = 10 (shed repentance minutes.

Question 1.

1. The number of people who come per minute after opening the door (10*4*20-400) 20=20 (people).

Open 6 entrances 400 (10*6-20) = 10 (minutes) 2, solution: A and B sell stools to cooperate, it takes 48 days to complete, then the work efficiency of A and B cooperation is 1 48;A does it alone for 63 days, and then B does it alone for 28 days, which is equivalent to 28 days of cooperation between A and B, and then 63-28 = 35 days by A alone, 28 days of cooperation can be completed 28 * (1 48) = 7 12, the remaining 1-7 12 = 5 12, A completes in 35 days, and A's work efficiency is (5 12) 35 = 1 84, then B's work efficiency is 1 48-1 84 = 1 112;

3. Xiao Zhao 7 * 5 + 4 = 39 points.

Xiao Li 7 * 55 + 4 = 389 points.

389-39 = 350 points.

Times, let's compare the two situations of picking up the driver with a car and meeting the driver on foot, you can get out, the section of the song infiltration distance that Manager Li walked is S, and the car has walked 2S less distance than usual, we can know that it takes minutes to walk the car for each S distance. Then we know that the time when the manager and the car met was 7:27:30, and the manager set off at 7:00, so it took the manager minutes to walk this distance. Now that we know how long it takes for the two to cover the same distance, the ratio of speed is also out (s