pennmou

12 people with previous experience in space flight， you have to choose exactly 1 person, so you have 12 ways to do that. And from the rest 9 people, you have to choose 2 of them, so it is 9*8=72, but wait, remember in this question order doesn't matter, so AB is the same as BA,(in 9*8, we assume that order matters, you choose A first and then B is one order and if choose B first and then A it is another order)  then you have to divide 72 by 2, that will get you 36.

so the total ways=36*12