1/( 1/x+ 1/y)= 6
1( 1/y+ 1/z)= 10
2/3/( 1/x+ 1/z)=5
Solution: x= 10
y= 15
z=30
A: It takes 65,438+00,65,438+05,30 days for each team of Party A, Party B and Party C to complete all the projects independently.
(2) Assume that Party A, Party B and Party C need to pay Party A, Party B and Party C the remuneration for their work every day.
6a+6b=8700
10b+ 10c=9500
5a+5c=5500
The solution is a=800 b=650 c=300.
Because the construction period requires that all projects be completed within 15 days, it can only be completed by Party A or Party B. ..
If A is finished, the cost =800* 10=8000.
B If completed, the cost =650* 15=9750.
Therefore, it costs the least to finish this project by Team A alone.