Judging from the meaning of the title, 400 x+900 y = 4200 x+y = 8,
X = 6y = 2,
A: Six for three days and three for seven days.
(2) Yes, for the following reasons:
If you book a regular ticket for a specified day and a three-day ticket for B, then the number of votes for seven days will be (10-a-b).
200 A+400 B+900( 10-A-B)= 4200。
7a+5b=48,
The solution is b=48? 7a5。
∵a and B are positive integers,
When a=4 and b=4,
∴ 10-4-4=2.
Book four ordinary tickets, four three-day tickets and two seven-day tickets on the specified date.
Xiao Li's idea can come true.