(1600+t)/80=60
1600+t=60*80
1600+t =4800
t=4800-1600
t=3200
2000/f-670=1330
2000/f=1330+670
2000/f-=2000
f=2000/2000
f=1
1300-(d-678)=400
d-678=1300-400
d-678=900
d=900+678
d=1578
(1600+t)/80=60
1600+t=60*80
1600+t =4800
t=4800-1600
t=3200
2000/f-670=1330
2000/f=1330+670
2000/f-=2000
f=2000/2000
f=1
1300-(d-678)=400
d-678=1300-400
d-678=900
d=900+678
d=1578