In how many different ways can letters of the word OFFICES be arranged?
A
2520
B
5040
C
1850
D
1680
E
None of these
Correct Answer: 2520
The given word contains 7 letters of which F is taken 2 times.∴ Required number of ways
$$\eqalign{ & = \frac{{7!}}{{2!}} \cr & = \frac{{7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1}}{{2 \times 1}} \cr & = 2520 \cr} $$