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Find the number of permutations of the letters of the word ‘ENGINEERING’ How many of these i. Begin with E and end with E ii. Have all the 3E’s together? |
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Answer» Total-11, N – 3, G – 2, 1 – 2, E = 3 Total permutations = \(\frac{11!}{3! \times 3! \times 2! \times2!}\) I. Number of permutations which begin with E & end with E is = \(\frac{9!}{3! \times 2! \times 2!}\) II. Number of Permutations in Which all 3E’s are together (Total 11 – 3 + 1 = 9′) = \(\frac{9!}{3! \times 2! \times 2!}\) |
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