5, 6, 3, 4, 1, ____
2
4
-2
6
Correct Answer : A
855,7695,69255,623295,_____
123, 211,299,156,244,____
There are 5 people - A, B, C, D, E, standing in a queue. How many ways are available to form the queue such that D is not ahead of E ?