Maths-
General
Easy
Question
Six ‘X's have to be placed in the square of the figure such that each row contains at least one X. In how many different ways can this be done
- 28
- 27
- 26
- None of these
The correct answer is: 26
In all, we have 8 squares in which 
have to be placed and it can be done in 
ways.
But this includes the possibility that either the top horizontal row does not have any 
or the bottom horizontal has no . Since we want each row must have at least one , these two possibilities are to be excluded. Hence required number of ways are 
.
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