Solution: (1) If the daily throughput of Party A is X 1, the daily throughput of Party B is X2, the working time of Party A is t 1, and the working time of Party B is t2, then:

X 1+X2=400

X 1=40t 1

X2=50t2

t 1 & gt； =t2 four types at the same time, 1600/9

(2) Based on the above settings, the unequal rents are as follows:

400t 1+600 T2 & lt； =4600

40t 1+50t2=400，t 1 >； =2.5

because

t2 & gt=0

400t 1 & lt； =4600

40t 1 & lt； =400 gives t 1

So 2.5 < = t1<; = 10