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Question

#plz check i got 21 ??? but answer is 86

Comments

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the problem is together not together

first put 6 1's it create 7 slot

select any 4 slot fronm them to put 0's

6!/6!*7C4=35

Answer 1

The necessary condition to be satisfied is:

 0 1 0 1 0 1 0

Now, there are remaining three 1's  that need to be placed:

_ 0 _ 0 _ 0 _ 0 _

Now, its like placing 3 identical balls into 5 different boxes.

That can be done in (5+3-1)C₃ ways = 35 ways

Comments

yes i m also geting 35