we are given
martians =4
plutonians =3
jupiterians=5
so, total number of seats =4+3+5=12
number of seating arrangement for martians is 4!
number of seating arrangement for plutonians is 3!
number of seating arrangement for jupiterians is 5!
total number of seating arrangement is 12!
so, we get
possible seating arrangements are
.............Answer