就会第一小题

1,
(2x+3y)*60=(2x+6y)*40
12x-8x=24y-18y
x=3y/2
2,
(2x+3y)*60=W
x=3y/2,即2x=3y代入上式:
(3y+3y)*60=W
W/y=360(本)
3,
两种奖品都要有:a>0,b>0,均为正整数;
(ax+by)*30=W
x=3y/2代入上式:
45ay+30by=W
45a+30b=W/y=360
1.5a+b=12
b=12-1.5a,
a=2,b=9;
a=4,b=6;
a=6,b=3;
a=8,b=0(舍去);
所以 a=2支,b=9本,或a=4支,b=6本,或a=8支,b=3本