For a job, it takes 4 hours for Party A and Party B to cooperate, 5 hours for Party B and Party C to cooperate, 2 hours for Party A and Party C to cooperate first, and 6 hours for Party B to complete the rest. It takes 6 hours for Party B to do this job alone______ It will be finished in two hours

For a job, it takes 4 hours for Party A and Party B to cooperate, 5 hours for Party B and Party C to cooperate, 2 hours for Party A and Party C to cooperate first, and 6 hours for Party B to complete the rest. It takes 6 hours for Party B to do this job alone______ It will be finished in two hours

It can be understood that Party A and Party B cooperate for 2 hours first, Party B and Party C cooperate for 2 hours, and Party C also does 6-2-2 = 2 hours, and completes 1-14 × 2-15 × 2 = 110 in 2 hours, so Party B does this work alone to 2 △ 110 = 20 (hours) a: Party B does this work alone to 20 hours

It takes four hours for Party A to cooperate with Party B, and five hours for Party B to cooperate with Party C. now let Party A and Party C work together for two hours, and the rest will be finished
How many hours does it take for B to finish alone?

It takes four hours for Party A and Party B to cooperate and five hours for Party B and Party C to work together. Now, Party A and Party C need to work together for two hours, and the rest of Party B needs six hours to finish. How many hours does it take for Party B to finish alone? Party A's work efficiency and 1 / 4 Party B's work efficiency and 1 / 5 Party A + 2 Party B + C = 1 / 4 + 1 / 5 = 9 / 20 first, Party A and Party C need to work together for two hours

For a job, Party A and Party B cooperate for 4 hours and Party B and Party C cooperate for 6 hours. Now, after Party A and Party C cooperate for 2 hours, Party B will complete the remaining 7 hours and Party B will finish it alone
How many hours does it take?

After 2 hours of cooperation between Party A and Party C, Party B will finish the rest in 7 hours
It's 2 hours for Party A and 2 hours for Party B and 3 hours for Party C
（1-1/4x2-1/6x2）÷3＝1/6÷3＝1/18
1÷1/18＝18
A B takes 18 hours