4 letter words from ACCOMMODATION There are different letters "ACCOMMODATION" namely, A, C, D, I, M, N, O, T 2‌2‌1‌1‌2‌1‌3‌1 Case ( 1 ) all 4 letters of the word are different numbers of combinations =‌8c4=70 Case (II) 2 letters are same and 2 are different. =‌4c1⋅‌7c2−6=78 ( ∵ when we select 2 same letter from 0 and 3rd letter also from, 0 then this need to be subtracted and such cases are 6 ) Case (III) When 3 letters are same =1.‌7c1=7 Case (IV) When 2 letters are same and other 2 are also same. =‌4c1×‌3c1=12 Hence, total number of combination =70+78+7+12=167