a group of astronauts
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12 has prev. experience.
9 doesn't have experience.
12*9*8=864.
I think this is the answer, not 100% sure.
9 doesn't have experience.
12*9*8=864.
I think this is the answer, not 100% sure.
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The problem with this approach is that you're double counting the inexperienced possibilities.EricLien9122 wrote:12 has prev. experience.
9 doesn't have experience.
12*9*8=864.
I think this is the answer, not 100% sure.
Let's call the 9 inexperienced astronauts a, b, c, d, e, f, g, h and i.
By simply multiplying 9*8, you've counted a then b and b then a as two different combinations, when in fact it's the same pair. Since you've doubled the number of options, you need to divide your final answer by 2.
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