Mathematics Olympiad questions, please ask experts to answer them in detail, urgent!! Thank you, hig

1) Because this is within 500 first (because no more than 500 yuan press 5 and then (3500-500) 15 (because more than 2000 yuan to 5000 yuan part of 15), so it is equal to 25 + 450 475 yuan.

2) 250-500 5 225 (this is within 500) 225 15 1500 (because this is 2000 to 5000 15), so 500 + 1500 2000

Hope it helps you o( o thank you.

Suffice it to say that this is not an Olympiad question.

And I would say that this is a super easy question, and it's definitely not an Olympiad.

-2000=1500 yuan.

500 yuan in 1500 needs to be paid according to 1, the amount to be paid is 500 5% = 251500, and the remaining 1000 yuan needs to be paid according to 2, and the amount to be paid is 1000 10% = 100 yuan.

So he should pay $125.

Partially 500 5% = 25 yuan.

The 2nd part is 1500 10% = 150 yuan, so the 3 parts also need to pay 250-150-25 = 75 yuan.

1. The truck catches up with the passenger car, which is exactly the tail of the car. then (250-180) (120-100) = seconds.

Walking in the opposite direction, it takes about 2 seconds to leave from the front to the rear of the car (250+180) (120+100).

2. It takes 8 seconds to get on a bridge, and 29 seconds to leave the bridge.

The front of the car actually walked on the bridge for 21 seconds. The train speed is 546 21 = 26 seconds meters.

The total length of the train is 26*8=208 meters.

546/(29-8)*8=208m。

3. A railway bridge is 1,000 meters long, and the time for the whole train to be completely on the bridge is 80 seconds.

Train speed: 1000 80 = m sec.

It was measured that the train took 120 seconds from the start of the bridge to the time it completely got off the bridge, and the time for the whole train to be completely on the bridge was 80 seconds.

Train length: meters.

4. 8=seconds.

124 Young Pioneers lined up in two columns, and there were 124 2-1 meters.

How long does it take for a team to get from the front of the line to the end of the line?

That is, the time from the time when the platoon is on the bridge to the time when the line is at the end of the line.

How much time does it take for the team to complete the length of the line plus the length of the bridge.

5. It takes seconds to miss all from the phase to the encounter, the length of train A is 300 meters, and the length of train B is 250 meters.

Then the sum of the speeds of the two cars is (300+250) m s.

Walk in the same direction, from catching up to missing all the seconds.

Then the speed difference between the two vehicles is (300+250) meters and seconds.

44-4 2=20 m-s 20+4=24m-s.

Inspection 24* meters.

One. 1.A truck is 250 meters long and has a speed of 120 meters per second, and a passenger train is 180 meters long and has a speed of 100 meters per second.

If two trains are traveling in opposite directions, how long does it take to leave from the front of the train to the rear of the train?

120x-100x=250 gives x= (2) set x seconds.

120x+100x=250-180 gives x=43 22s2Let x m x 8 *29 = 546 + x get x = 192 m.

3.Let the length of the car be x meters and the speed will be y meters s

Equation 1000 + x = 120y

x=40y gives x=500m y=

4.The team length is 123*

The distance to be passed is 124+

Minute. 5.Let the velocities of A and B be x and y respectively

The system of equations gives x=27 y=23 (

1.(1) Set x seconds.

120x-100x=250 gives x=

2) Set x seconds.

120x+100x=250-180 gives x=43 22s2The length of the bridge is x meters.

x 8 * 29 = 546 + x gives x = 192 meters.

3.Let the length of the car be x meters and the speed will be y meters s

Equation 1000 + x = 120y

x=40y gives x=500m y=

4.The team length is 123*

The distance to be passed is 124+

Minute. 5.Let the velocities of A and B be x and y respectively

The system of equations gives x=27 y=23 (

1.(1) (250-180) (120-100) = seconds.

2) (250 + 180) (120 + 100) = 43 22 seconds.

26*8=208m

3.(120-80) 2+80=100 seconds.

1000/100=10m

10*（120-80）/2=200m

Name 62-1 = 61 61*

124+ points.

5.(300+250) msec).

(300+250) msec).

44+4) 2 24 (ms).

44-4) 2 20 (ms).

1. x=3y=52, no.

Obviously no matter how it is assembled.

This five-digit number must be a multiple of 3.

No matter how the group is.

Prime number. 3、x=6

If I tell you how to solve the problem, I will tell you that the answer doesn't seem to be very good, hehe.

Solution: The original water in the pool is x cubic meters, and the drainage of the drainage pipe per hour is y cubic meters according to the topic, x+100 10*6+100 15*6=y*6x+100 10*2+y*2

Thus we get, x=20

A: The original water in the pool is 20 cubic meters.

2) Let the concentration of 40% and 10% brine have x and y grams respectively, according to the meaning of the topic, 40%*x+10%*y=(x+y)*30%40%*x+10%*y+300*20%=(x+y+300)*25% can be obtained, x=200, y=100

A: 200 grams of salt water with a concentration of 40%.

1.(6 10 + 6 15-2 10) (6-2) 100 = 20 cubic meters – displacement per hour.

Original water (20-100 10) 2 = 20 cubic grams – 30% brine after mixing.

40% saline 300 (30%-10%) 40%-10%) = 200 grams.

This is also an Olympiad problem?! This book editor can be regarded as a ......

A and B are kilometers apart, and they are walking in the opposite direction. A walks kilometers per hour, and B travels kilometers per hour. A walks for 25 minutes before B leaves, and B meets a few minutes after he leaves?

( = hours = 78 minutes.)

A certain unit marched a long distance to a certain place for 12 days, and the average daily march distance was reduced by 5 kilometers, so that the remaining 366 kilometers of the journey would have to travel for 15 days.

The total distance of this march was x kilometers.

Set the last day to walk x km.

x + x+14*5)*15/2 = 366

x is a negative number, and the data may be incorrect.

A and B set up a company in partnership, and A's shares are times that of B. Now C wants to take a stake in the company, and the three of them agree that C will spend 15 million yuan to buy part of the shares of A and B, so that each of the three of them will account for one-third of the shares. So how much does C pay A?

1500*3 ( = 18 million yuan -- B's original shares.

1500*3 - 1800 = 27 million yuan -- A's original shares.

2700-1500 = 12 million yuan C pays 12 million yuan to A.

Mom gives Honghong some money to buy greeting cards, there are three kinds of greeting cards A, B and C, each yuan for a greeting card of type A, and each yuan for a greeting card of type C, and it is necessary to buy 8 more cards for type A than for type B, and 6 more cards for type B than for type C cards, how many pieces does mother give to Xiaohong? How much is each type B card?

Set the mother to give Xiaohong x yuan, and the B card each y yuan.

x/ = x/y + 8

x/y = x/ + 6

x = 12y =

The second question on the 1st floor doesn't seem to be right, wow, this is a question of the difference series, I don't know if the landlord has learned, don't use the formula to do it, it may be a little complicated.

First, use 366 to calculate the number of distances traveled on the 13th day.

x+x-5+x-2*5+……x-14*5=36615x=366+5*7*15

x=the same way as the previous 12 days=

Just add 366 at the end.

(1) 78 minutes (2) a little wrong (3) 12 million yuan (4) yuan.

1. Analysis: From the beginning to the second encounter, A walked the journey from A to B and returned, B walked the journey from B to A and returned, and then the two walked twice the distance, so when the two met for the second time, the two walked a total of three times the distance of AB. From the beginning to the first meeting, the two walked twice as much, and A walked 500 meters at this time.

Therefore, when the two of them walked three times the distance, A walked a total of 500*3, that is, 1500 meters. The second encounter between A and B is 600 meters away from place B, that is, A arrives at place B and returns and walks 600 meters to meet B, so the distance traveled by A is AB distance + 600 meters = 1500 meters, so AB distance is 900 meters. In the same time, A walked a total of 1500 meters, and A and B walked 900*3=2700 meters, so B walked 2700-1500=1200 meters.

The velocity ratio of A and B is 1500:1200=5:4

Column formula: 500*3=1500 (meters).

1500-600 = 900 (meters).

900*3-1500=1200 (meters).

2. Analysis: The ratio of the speed of A and B is 3:5, so when A and B meet, the ratio of the distance traveled is 3:

5, (look at the picture I drew, the red line is the route taken by A), the difference between the third and fourth times is 100 meters, a total of eight squares, and the distance is 200 meters.

3. A left place B and walked for 15 minutes, which is 1200 meters, so A fell B a total of 1200 * 2 = 2400 meters. And because A rests for 30 minutes, A doesn't walk in these 30 minutes, if A walks in these 30 minutes, A will walk out 30 * 80 = 2400 meters, that is, 2400 meters more than B, that is, if the two people don't stop from the beginning to the time they meet, the difference between the two is 2400 + 2400 = 4800 meters. Because A walks 20 meters more than B per minute, then a total of 4800 20 = 240 minutes are walked from the beginning to the meeting.

The time for A to walk from A to B is 240-30-15 = 95 minutes, 80 * 195 = 15,600 meters.

1200*2=2400 meters.

30*80=2400 meters.

2400 + 2400 = 4800 meters.

4800 (80-60) = 240 (minutes).

240-30-15)*80=15600 meters.

Draw a line diagram and take a look.

A and B met for the first time, and a total of 1 whole course.

Among them, A traveled 500 meters.

A and B met for the second time, and a total of 3 whole journeys.

Among them, the first line took 1 full course plus 600 meters.

A and B have a total of 3 full journeys, and the time taken is 3 times that of 1 full journey.

A should be OK: 500 3 = 1500 meters.

That is: 1 full journey plus 600 meters equals 1500 meters.

The distance between AB is: 1500-600=900 meters.

Then when they first met, B went to Chuncha: 900-500 = 400 meters.

The velocity ratio of A and B is 500:400=5:4

The velocity ratio of A and B is 15:25=3:5

A and B have a total of 1 full journey, and A has 3 (3+5) = 3 8 full journeys.

A and B meet for the third time, a total of 2 3-1 = 5 full courses.

Among them, A has 5 3 8 = 15 8 full courses.

The distance between the meeting point and A is 2-15 8 = 1 8 A and B meet for the fourth time, and a total of 2 4-1 = 7 whole journeys.

Among them, A has 7 3 8 = 21 8 full courses.

The distance between the punctual point of the encounter and a is 21 8-2 = 5 8 of the whole journey, and the distance between the third meeting point and the fourth meeting point is the whole journey.

ab distance: 100 1 2 = 200 km.

When A and B met, they traveled twice as much.

When A arrives at B, the distance between B and B is:

30 60 + (80 + 60) 15 = 3900 meters.

In other words, at this time, A has traveled 3,900 meters more than B.

Per minute, A has more rows than B: 80-60 = 20 meters.

It takes a lot to get from A to B: 3900 20 = 195 minutes.

ab distance: 80 195 = 15600 meters.