Solution: AB distance = (4.5× 5)/(5/11) = 49.5 km.
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 journey, the truck and the bus met for 28 kilometers. How many kilometers is it between A and B?
Solution: 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 both of them start from the same place at the same time. After B meets A, it will take another 4 hours to return to the original starting point. B How long does it take to go around the city?
Solution: The speed ratio of A and B = 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 Party A completes the whole journey of 1\\4, Party B is still 640 meters away from Location B. When Party A completes the remaining 5\\6, Party B completes the whole journey of 7\\ 10. How far is the distance between the two places?
Solution: 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 it takes 7 hours for car B to complete the journey. Three hours after the departure of the two cars, the distance is15km. What is the distance between a and b?
Solution: Case A: 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?
Solution: 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 to finish. Now Team A and Team B have been working together for three days, and the rest of the projects are completed by Team B alone as planned. How many days is the specified date?
Solution: 3 days of A is equivalent to 5 days of B.
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?
Solution: B completed 5× 1/30= 1/6 in 5 days.
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?
Solution: the sum of the working efficiency 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 currently 187 pieces to be processed. If it is stipulated that three people spend the same amount of time to finish it, how many parts will each person have to process?
Solution: It takes 1/4 hours, 2/5 hours and 1/5 hours to process1parts 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 Team A and Team B is 2: 3. How many days does it take for Team A and Team B to finish this project independently?
Solution: The working 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?
Solution: Take everyone's workload as the unit 1.
It is also necessary to increase/kloc-0 /× 25× 20/(/kloc-0 /× 20)-20 = 25-20 = 5 people.
15. For a project, Party A will do it for 3 days first, and then Party B will join in. Two-thirds of the projects completed after 4 days are 1 and three-quarters of the projects completed after 10. A was transferred because of some things, and B did the rest. How many days did a * * * do?
Solution: according to the meaning of the problem
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.