2(X+2Y)=560
4(X+Y)=800
Solution: X= 120 Y=80.
(2) The maximum number of students in the school may be 45*8*4= 1440.
The number of people who can pass in 5 minutes is (120+80)*2*5=2000.
The actual number of people who passed is 2000 * (1-20%) =1600.
1600 > 1440
Therefore, the four doors built meet the safety requirements.