AB distance = (4.5× 5)/(5/11) = 49.5km.
2. A bus and a truck leave from Party A and Party B at the same time. The speed of a truck is four-fifths that of a bus. After a quarter of the whole journey, the truck met the bus 28 kilometers away. How many kilometers is it between Party A and Party B?
The speed ratio of passenger cars and trucks is 5: 4.
Then the distance ratio when meeting is 5: 4.
When they met, it was 4/9 of the whole truck journey.
At this time, the truck has traveled all the way 1/4.
4/9- 1/4=7/36 from the meeting point.
Then the whole journey = 28/(7/36) = 144km.
3. Party A and Party B walk around the city, with Party A walking 8 kilometers per hour and Party B walking 6 kilometers per hour. Now they all set off from the same place with their backs to each other. After meeting with Party A, Party B needs 4 hours to return to the original starting point. How long does it take Party B to visit the city?
The speed ratio of Party A and Party B is 8: 6 = 4: 3.
When they met, B walked 3/7 of the way.
Then 4 hours is 4/7 of the whole trip.
Therefore, the time spent on line B in a week =4/(4/7)=7 hours.
4. Party A and Party B walk from place A to place B at the same time. When A walks 14, B is 640 meters away from B. When A walks the remaining 56, B walks 7 10. How far is the distance between the two places?
After A left 1/4, the remaining 1- 1/4=3/4.
Then the remaining 5/6 is 3/4×5/6=5/8.
At this time, a * * * left 1/4+5/8=7/8.
Then the distance ratio between Party A and Party B is 7/8: 7/ 10 = 5: 4.
So when A goes 1/4, B goes 1/4×4/5= 1/5.
Then AB distance =640/( 1- 1/5)=800 meters.
5. Two cars, A and B, start from A and B at the same time and drive in opposite directions. Car A travels 75 kilometers per hour, and car B takes 7 hours to complete the journey. After three hours, the distance between the two cars is15km. What is the distance between a and b?
One situation: Party A and Party B have not met yet.
3/7 of the 3-hour journey of the B train.
The three-hour journey is 75×3 = 225 kilometers.
AB distance = (225+15)/(1-3/7) = 240/(4/7) = 420km.
In one case, Party A and Party B have met.
(225- 15)/( 1-3/7)= 2 10/(4/7)= 367.5km。
9. For a batch of parts, if Party A and Party B work together for 5.5 days, it can exceed 0. 1 of the batch of parts. Now Party A works for 2 days, then Party A cooperates for 2 days, and finally Party B works for 4 days to complete the task. If Party B works alone, how many days can this batch of parts be completed?
Treat all parts as a unit 1.
Then the sum of the work efficiency of Party A and Party B = (1+0.1)/5.5 =1/5.
The whole process is that A works 2+2=4 days.
B working 2+4=6 days.
It is equivalent to 4 days of cooperation between Party A and Party B, and 1/5×4=4/5 is completed.
Then B does it alone for 6-4=2 days 1-4/5= 1/5.
So it takes 2/( 1/5)= 10 days for B to complete it alone.
10, there is a project to be completed within the specified date. If Team A does it alone, it will be finished on schedule. If Team B does it alone, it will take more than 5 days. Now Team A and Team B have been working together for three days, and the rest of the project will be completed on schedule by Team B alone. How many days is the specified date?
Three days is equivalent to five days.
The work efficiency ratio of Party A and Party B is 5: 3.
Then the ratio of completion time between Party A and Party B is 3: 5.
So it takes 3/5 time for A to complete.
So it takes 5/(1-3/5) = 5/(2/5) =12.5 days for B to complete it alone.
Specified time = 12.5-5=7.5 days.
1 1. A project will be completed in 20 days by team A and 30 days by team B. Now team B will finish it in five days, and the rest will be completed by team A and team B. How many days will it take?
B 5 days to complete 5 x 1/30 = 1/6.
The work efficiency of Party A and Party B =1/20+1/30 =1/6.
Then (1-1/6)/(1/6) = (5/6)/(1/6) = 5 days.
12. It takes 15 days for Party A to complete a project, 15 days for Party B, and 20 days for Team C. The three teams work together, and Team A has left because of something. It took six days. How many days did Team A actually work?
The sum of the working efficiencies of ethylene and propylene =115+1/20 = 7/60.
Do both B and C for 6 days, and finish 7/60×6=7/ 10.
A complete1-7/10 = 3/10.
Then A actually made it (3/10)/(110) = 3 days.
12. It takes 4 hours for Party A, 2.5 hours for Party B and 5 hours for Party C to process a part. There are 187 parts to be processed now. If three people are required to finish it at the same time, how much does each person have to process?
Processing 1 part takes 1/4 hours, 2/5 hours and 1/5 hours respectively.
Then the completion time =187/(1/4+2/5+1/5) =187/0.85 = 220 hours.
Then a treatment 1/4×220=55.
B processing 2/5×220=88 pieces.
C treatment 1/5×220=44.
13. A project was completed by Party A on May1,and then completed by both parties, which took 16 days. It is known that the efficiency ratio of Party A and Party B is 2: 3. How many days does it take for Party A and Party B to complete the project independently?
The sum of the work efficiency of Party A and Party B = (1-1/5)/16 = (4/5)/16 =1/20.
A's work efficiency =1/20× 2/(2+3) =1/50.
Party B's work efficiency =1/20-1/50 = 3/100.
Then it takes1(1/50) = 50 days for A to complete it alone.
It takes1(3/100) =100/3 days =33 days and 1/33 days.
14, a project, a team of 20 people do it alone for 25 days. If it takes 20 days to complete, how many people need to be added?
Think of everyone's workload as a unit 1.
It is also necessary to increase/kloc-0 /× 25× 20/(/kloc-0 /× 20)-20 = 25-20 = 5 people.
15, for project a, it will take three days for A, then B will join, four days after the project is completed 1, and three quarters after the project is completed 10. A was transferred because of something, and the rest was made by B. How many days did a * * * work?
According to the meaning of the question
The cooperation between Party A and Party B began in 4 days13 and ended in 3/4 days 10.
So the cooperation between Party A and Party B is10-4 = 3/4- 1/3=5/ 12 in 6 days.
Therefore, the work efficiency of both parties is =(5/ 12)/6=5/72.
Then the working efficiency a = (1/3-5/72× 4)/3 = (1/3-5/18)/3 =1/54.
Party B's work efficiency = 5/72-1/54 =11/216.
Then B needs to complete the remaining (1-3/4)/(11/216) = 54/11day.
A * * * made 3+10+54/1=17 and10//day.