1 y=c+i+g=100+0.8(y-0.25y+62.5)+200+200=1450+0.6y y=3625

2 k=1/[1-0.8*(1-0.25)]=2.5

3 税收T=0.25Y=0.25*3625=906.25 财政盈余=T-G=906.25-200=706.25

4.Y=100+0.8(Y-0.2Y+62.5)+200+200=1450+0.64Y Y=4027.78

k=1/[1-0.8*(1-0.2)]=2.78