Stuck here : there are 100 objects labeled 1, 2,...100. They are arranged in all possible ways. How many arrangements are there in which object 28 comes before object 29.
My approach : Consider object 28 & object 29 , a single object. Now we have a total of 99 objects which can be per mutated in 99! ways . But the answer is 4950*98! .
What's wrong with my approach?