6000/x=6000/ 1.5x+40

x=50

2. Solution: It takes X days to set up.

50x+75x=6000

x=48

3. Solution: Party A works for X days and Party B works for Y days.

50x+75y=6000

And x+y≤60 (solving equation)

y= 12

x=48

All right.