In how many different ways can the letters of the word OPERATE be arranged ?
In how many different ways can the letters of the word OPERATE be arranged ? Correct Answer 2520
The given word contains 7 letters out of which E is taken 2 times and all other letters are different .∴ Required number of ways
$$\eqalign{ & = \frac{{7!}}{{2!}} \cr & = \frac{{7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1}}{2} \cr & = 2520 \cr} $$