Hey guys- this is in the Timed Quant Practice Medium Section 2, and I cannot seem to get to the answer. I know this is a Permutation, and I am trying different ways of “choosing” but I cannot get to 12. I think the idea of only one comedy act is really throwing me off.
Do casework with D_1 and D_2, so it’d look something like this:
D_1 _ D_2 _ _
D_1 _ _ D_2 _
D_1 _ _ _ D_2
_ D_1 _ D_2 _
_ D_1 _ _ D_2
_ _ D_1 _ D_2
Now count the number of arrangements such that the two singing acts are not together. As a hint, an easy way to count this would be to position the comedy act in specific positions.
