Re: Gita, Hussain, Inge, Jeong, Karen, and Leila are seated in a row of
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20 Jul 2021, 18:54
I got this wrong the first time. Where did I go wrong? Well here it is.
We have G,H, I, J, K and L.
Lets take JL as one item, and G,H,I and K as other items. So, now we have 5 items to arrange = 5! = 120 ( Not included arrangements in which LJ sit together; JL is different arrangement from LJ)
Correction: 5! * 2 = 120 * 2 = 240
But we CANNOT let G and I sit together. Lets find out in how ways among above arrangements G and I do sit together.
Take JL and GI as two items, and H and K as other items. In total, we have got 4 items to arrange = 4! = 24 (Again, I did not include JL and IG)
Correction: 2 * 2 * 4! = 24 * 4 = 96
Therefore, excluding those in which G and I sit together, we will have 120 - 24 = 96 ways to seat them all.
Correction: 240 - 96 = 144