2) Answer: 8550. Solution. (Someone got it right)
3) Answer: 1 kg of flour. Solution: The flour obtained by the last person after conversion into the equation is 1- (half1+21+21× 32× 41+... (Write it yourself, write it yourself. +.....+( 1992× 1993) 1 = 1-( 1-2 1-3) 1- 1 in 0993)= 1-( 1- 1 in 0993) = 1 so1993x1993+0 =1kg.
4) 1. A: This question is not rigorous (having an empty car does not mean that all other cars are full). There are four answers: A. One * * *, 240 people; B. There are 285 people; C. There are 330 people; D. There are 375 people. Solution: Equation, 45x+15 = 60x (x-1)-k (k is the seat that may be vacant in a 60-person car).
2. Answer: Different people have different prices. It is more cost-effective to rent a bus for 45 people under the same circumstances. A. 1 180 yuan (four 45 people 1 60 people) b. 1400 yuan (five 45 people 1 60 people) c. 1620 yuan (six 45 people 65438
5) A: Yes 180 * *. Solution: 100 to 999 * * * has 900 three digits, 100 to 109 is a group, and then every ten digits are a group. It is found that the sum of numbers is 10 continuous natural numbers. And every 10 consecutive natural numbers, there must be two numbers that are multiples of 5, so the sum of the multiples of 5 * * * has 900×5 of 1 = 180.
6) A: Ranked in the second column of line 499. Solution: Someone is wrong. Every 8 numbers are divided into 1 group, 1993 ÷ 8 = 249 and 1. Because each group has two rows, the number of 1 in 249× 2+ 1 = 499 rows is 1 column, which is also the second column.
7) the topic is not rigorous (the conditions are not enough), so it can't be done. Please send me a message if you have the answer. )
8) Answer: There should be several each. There are three situations: a.4 cocks, 18 hens and 78 chickens; B 8 cock, 1 1 hen, 8 1 chick; C. 12 roosters, 4 hens and 84 chickens. Solution: Let X be the number of roosters, Y the number of hens and Z the number of chickens. Equations: 5x+3y+ 1z = 100.
x+y+z= 100
Three groups of solutions are obtained.
9) A: There will be a draw at most. Solution: the third place scored 7 points, which proved that he could only win two games, draw one game and lose one game. Because there were four draws and * * * played 12 (calculated), the total score of the whole game was 3× 8+ 1× 4 = 28 points. The total score of the first place, the second place and the third place is at least 24, so the sixth place is 0, the fifth place is 1 and the fourth place is 3.
A: 880 Li. Solution: Because the time for the host to leave is 3/4 to 1 day = 65438+5/02 days, the time for catching up in time is 65438+5/02 = 5/24 days. When the host was chasing, the guest left: 5 × 300 = 62.5 miles, so the host would.
1 1) answer: 16 eggs. Just list the equations. Someone got it right, but the final answer was wrong.
12) answer: 200 yuan, paperhanger 900 yuan, painter 800, electrician 300 yuan, carpenter 3000 yuan, cement worker 2300 yuan. Someone has already done it. It's also an equation.
13) a * * * has 600 chickens. Solution: There are X chickens.
20×(x-75)= 15×(x+ 100)
Get x = 600.
14) a: 7 minutes and 24 seconds. Let the human speed be v and the wind speed be v.
3×(V people +V wind) = 4× (V people -V wind)
Solution, V people = 7V wind.
So, 7 8V people x 3 = 1 mile.
So, V people = 7/24 miles per minute, so walk 1 need124 minutes.
15) A: My son is 5 years old, a countryman is 50 years old, my wife is 25 years old, and my daughter is 1 year old. Someone did the right thing. Or a series of equations.