In how many different ways can the letters of the word RIDDLED be arranged?
A. 840
B. 1680
C. 2520
D. 5040
E. None of these
Answer: Option A
Solution (By Examveda Team)
The given word contains 7 letters of which D is taken 3 times.∴ Required number of ways
$$\eqalign{ & = \frac{{7!}}{{3!}} \cr & = \frac{{7 \times 6 \times 5 \times 4 \times 3!}}{{3!}} \cr & = \left( {7 \times 6 \times 5 \times 4} \right) \cr & = 840 \cr} $$
This Question Belongs to Arithmetic Ability >> Permutation And Combination
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