1. There are 180 red, white and black beads of the same size, arranged in five red, four white and three black. Q: what color is the 158th one? How many black beads are there? 2. There is a row of colored lights on the roadside. There are red, yellow and green lights between the two white lights. Then, what color is the 80th light?

1. There are 180 red, white and black beads of the same size, arranged in five red, four white and three black. Q: what color is the 158th one? How many black beads are there? 2. There is a row of colored lights on the roadside. There are red, yellow and green lights between the two white lights. Then, what color is the 80th light?

180 ÷ (3 + 4 + 5) * 3 = 45 red; white

In a certain meeting, there were 700 more male Representatives than female representatives yesterday. Today, there are 1 / 10 fewer male representatives and 1 / 20 fewer female representatives. Today, there are 1999 people attending the meeting. How many people attended the meeting yesterday?
Disable the equation! And write a formula to find what

If we regard female representatives as unit 1, then male representatives are 700 more than unit 1. At this time, the number of male representatives is reduced by 1 / 10, which is 9 / 10 and 700 × (1-1 / 10) = 630, and the number of female representatives is 1-1 / 20 = 19 / 20. Then the original number of female representatives is (1999-630) / (9 / 10 + 19 / 20) = 1369 / (37 / 20) = 740

1. Remove the decimal point of a decimal and add it to 4 times of the original number. The sum is 702. What is the original decimal?
2. There are several apples and pears. The number of apples is three times that of pears. If you eat two pears and five apples every day, there will be 20 apples left when the pears are finished. How many pears are there?
3. There are 351 bags of rice and flour in the canteen. If 20 bags of rice are added and 50 bags of flour are reduced, then the number of rice bags is more than 3 times that of flour bags. How many rice bags and flour bags are there?
``And give me the formula and the result, I give him 5 points more!

1. Because the final result is an integer, so the original decimal and 4 multiplied must be an integer, this decimal can only be one decimal place, or two decimal places. If it is a decimal place, 702 / (10 + 4) = 50.14285 does not meet the requirements. If it is two decimal places, 702 / (100 + 4) = 6.75, the original decimal is 6.752, the number of pears = 20 / (3 / 5-1 / 2) = 2

As shown in the figure, if the straight line ab ∥ ed, can you deduce the quantitative relationship between ∥ ABC, ∥ BCD, ∥ CDE? Please give reasons

Reasons: CF ∥ De, ∥ ab ∥ ed, ∥ ab ∥ de ∥ CF, ∥ 1 + ∥ CDE = 180 °, ∥ 2 = ∥ ABC, ∥ BCD + ∥ CDE - ∥ ABC = 180 ° through point C

1. There are two beakers with 85 grams of water in total. One fifth of the water is poured out from the first beaker, and then 4.1 grams of water is poured into the second beaker. The two beakers contain the same amount of water. So how many grams of water are in each beaker?
2. Koizumi and Ou Ou go from Koizumi's house to rabbit's house together. Koizumi's walking speed is 5km / h for the first third of the journey, 4.5km/h for the middle third, 4km / h for the last third, and 5km / h for the first half of Ou ou, It is known that Koizumi arrived 30 seconds earlier than Ou Ou ou, so how many kilometers is the distance from Koizumi's house to rabbit's house?
3. In 2012, Li Ming read the story of a late mathematician. He found that the mathematician's age at the time of his death was exactly one 34th of the number of A.D. when she was born. How old was the mathematician's grade when he published a famous mathematical paper in 1970?
4. Li Ming and his mother went out to see a movie in the evening. When they left home, they saw that the clock at home showed exactly 7 o'clock. When they came home from a movie, the hour hand and minute hand on the clock just coincided, and they were between 9 and 10. How many minutes did Li Ming go through from leaving home to returning home?
5. There are 100g, 200g and 300g of water in the three test tubes a, B and C. pour 100g of salt water of certain concentration into a, mix well, take 100g out of a and pour into B, mix well, take 100g out of B and pour into C. finally, the concentration of salt water of C is 0.75%. What is the concentration of salt water poured into test tube a at the beginning?

1. Let the first cup contain x grams of water, and the second cup contain (85-x) grams of water
x=49.5,85－x=35.5
2. 9 km
3. 23 years old
4. 2 hours and (49 + 1 / 11) minutes
The above answers have been checked
I haven't thought of the fifth question for the moment. When I do, I'll send it by my trumpet

A section of dyke near the sea is 15 meters above sea level, a lighthouse is 50 meters above sea level, and a submarine is 25 meters below sea level
How to express the heights of nearby lighthouses and submarines?
Is it positive or negative?

Yes, but pay attention to who is the benchmark
The question is not based on the sea level as we usually think, but on the height of the dyke on the seashore, which is recorded as 0 meters. The height of the lighthouse and submarine is different from that of the sea level, so the calculation of the height of the lighthouse and submarine should be based on the dyke
The dam is 15 meters above the sea level. First, mark it as + 15 meters, but remember that it is the real "0" when doing questions
The lighthouse is 50 meters above the sea level, which should be + 50 meters, but the datum line has changed, so 50-15 = 35, which should be expressed as + 35 meters
When the submarine is 25 meters below sea level, it should be - 25 meters. Similarly, the datum line has changed, so 15 + 25 = - 40 should be expressed as - 40 meters
Don't know, ask again!

A group of workers went to site a and site B to clean up. The workload of site a was 112 times that of site B. in the morning, the number of workers going to site a was three times that of site B. in the afternoon, 712 of these workers went to site a and the other workers went to site B. by evening, the work of site a had been finished, and the work of site B needed four workers to do another day. So this is the best time How many workers are there______ People

The number of people going to site a in the morning is the total number of people: 3 △ 1 + 3 = 34 the number of people going to site B is the total number of people: 1-34 = 14 the number of people going to site B in the afternoon is the total number of people: 712 the workload of site a (34 + 712) × 12 = 23 the workload of site B 23 △ 32 = 49 the workload completed by site B: (14 + 512) × 12 = 13 the remaining workload 49 − 13 = 19 the total number of people is 4 △ 19 = 36 (people) a: this There are 36 workers in the batch

What is the distance between the starting point and each lane in the 200 meter race?

Length of each track of conventional runway:
Runway length (m)
1 400
2 407.04
3 414.70
4 422.34
5 430.03
6 437.70
7 445.36
8 453.03
It is estimated that the difference between each track of 400m should be about 3M 8

To write a clear idea
1. For a fraction, the sum of numerator and denominator is 30. If 3 is added to numerator and 31 is added to denominator, the new fraction will be 1 / 3. What is the original fraction?
2. A kind of water plant can double its growth every day. Put one such plant into a pool and the pool will be full 21 days later. How many days will it be half of the pool?

The sum of numerator and denominator of a fraction is 30. If numerator plus 3 and denominator plus 31, the new fraction is about 1 / 3. First calculate the sum of numerator and denominator of the new fraction, which is 30 + 3 + 31 = 64. Put the average score of 64 in numerator and denominator, and put the other three in denominator. Then subtract the new fraction by 3 and denominator by 31

Is the concept of "East, West, north, South" applicable to any part of the earth?

No, in the south pole of the earth, all sides are north, in the north pole of the earth, all sides are South