Answer:
I think number 1=209
number 2=120
number 3=89
Step-by-step explanation:
x= 1st aircraft
y=2nd aircraft
z=3rd aircraft
x=y+89
y=z+31
z=y-31
x+y+z=418
y+89+z+31+y-31=418
2y+89+z=418
2y+z=329
2y+(add z)
2y+y-31=329
3y=360
y=120
x=120+89=209
z=120-31=89