Problem Solving

jogi1984 wrote:In how many different ways can the letters A, A, B, B. B, C, D, E be arranged if the letter C must be to the right of the letter D?


1,680
2,160
2,520
3,240
3,360

There are 8 letters out of which A appears 2 times and B appears 3 times.
So, without any restriction, total arrangements = 8!/(2! * 3!) = 3,360
In half of the cases D will be to the right of C and in half of the cases it will to the left of C, so the required no. of ways = 3,360/2 = 1,680

The correct answer is A.