Solution: If Factory A needs to treat garbage for x hours every day, then Factory B needs to treat garbage for (700-55x)/45 hours every day.

550 x+495 *(700-55x)/45 & lt； =7370

x & gt=6

So a factory needs to dispose of garbage for at least 6 hours every day.

(<= less than or equal to, > = greater than or equal to)