The distance between Party A and Party B is the same, and the time for Party A is 5 hours less, so it takes t hours to form Party A..
free
1. 12t=8(t+5)
t= 10
So the distance = 120km.
Xiaoming and Xiao Fang are running by a pond. They started from the same point and walked in the same direction. Xiao Ming: 280 m/min; Xiao Fang: After 220 minutes and 8 minutes, Xiao Ming caught up with Xiao Fang. How many meters is this pond in a week?
280*8-220*8=480
At this time, if Xiao Ming catches up the first time, it will be like this.
At this time, Xiao Ming ran again. ...
1. Use 3.5.7.0 to form a two-digit number, and the product of () multiplied by () is the largest. The product of () multiplied by () is the smallest.
2. Some blocks have more than 50 blocks and less than 70 blocks, every 7 blocks 1 block, every 9 blocks 1 block, or 1 block. How many blocks are there?
3.6 Potted flowers should be arranged in 4 rows with 3 pots in each row. How should we arrange them?
Four people from Class 4.4 (1) participated in the 4X50 relay race. How many different arrangements are there?
5. Can you choose five numbers from the picture on the right so that their sum is 60? Why? 15 25 35
25 15 5
5 25 45
6.5 The sum of consecutive even numbers is 240. What are five even numbers?
7. From A to B, someone rides a motorcycle 12 hours, and then rides a bike for 9 hours. When he returned, he rode his bike for 2 1 hour and then rode his motorcycle for 8 hours. How long does it take to get from a to b by motorcycle?
1 70*53 Maximum 30*75 Minimum
2 64 yuan
Three-dimensional pentagram
4 4*3*2* 1=24
5 can't, because they are all odd numbers, and it is impossible to get even numbers by adding odd numbers.
6.240/5=48, then the remaining even numbers are: 48-2 = 46, 48-4 = 44, 48+2 = 50, 48+4 = 52.
7. The motorcycle speed is xkm/h and the self-propelled speed is ykm/h..
2 1y+8x= 12x+9y
4x= 12y
x=3y
So the motorcycle * * * takes 12+9/3= 15 hours.
Question 1 If the sum of a four-digit number and a three-digit number is 1999, and the four-digit number and the three-digit number are composed of seven different numbers, how many such four-digit numbers can there be at most?
This is the fourth question in the final examination paper of the 15th "Spring Cup" primary school students' mathematics competition in Beijing, and it is also the question that the contestants lose the most points.
Get a = 1, b+e = 9, (e ≠ 0), c+f = 9, d+g = 9.
In order to calculate the maximum number of such four digits, conditions A, B, C, D, E, F and G are different from each other. It can be seen that there are seven ways to choose B (B ≠ 1, 8,9) and six ways to choose C (C ≠ 1, 8,9).
After answering the question 1, if we think further, it is not difficult to think of the following question.
Question 2: There are four cards with the number 1 written on both sides. The first card has 0 and 1, and the other three cards have 2 and 3, 4 and 5, 7 and 8 respectively. Now, take out three cards at random and form a row. How many different three digits can a * * * make up?
This is the preliminary examination question of the 14th "Spring Cup" mathematics competition for primary school students in Beijing. The solution is as follows:
After that, 10 digit b can take the six digits of the other three cards; The last digit c can be four digits of the remaining two cards. To sum up, a * * * can form different three digits * * (7× 6× 4 =) 168.
If 67 tons of goods are moved from warehouse A to warehouse B, then the goods in warehouse A are exactly twice as much as those in warehouse B; If 17 tons of goods are moved from warehouse A to warehouse B, then the goods in warehouse A are exactly five times that in warehouse B, so how many tons of goods are stored in each warehouse?
67×(2+ 1)- 17×(5+ 1)
=20 1- 102
=99 (ton)
99÷〔(5+ 1)-(2+ 1)〕
=99÷3
=33 (tons) A: It turns out that B has 33 tons.
(33+67)×2+67
=200+67
=267 (tons) A: It turns out that A has 267 tons.
Analysis:
1. If 67 tons of goods are moved from warehouse A to warehouse B, the goods in warehouse A are exactly twice as much as those in warehouse B;
The total number of a and b has not changed. The total includes 2+ 1=3 current b, that is, the original b plus 67. So the total includes three original B's and three 67's [67× (2+1) = 201].
2. If 17 tons of goods are moved from warehouse A to warehouse B, then the goods in warehouse A are exactly five times that of warehouse B,
Same reason as above, total