Combinations
 

Combinations problem 18


Electronic circuit consists of 5 ON-OFF switches (on or off switch). How many possible combinations are there if:


  • switches are in any position,


  • we know that the third switch must always be on,


  • we know that three series switches are always on and the other two are in any position,


  • we know that two series switches are not in the same positions,


  • we know that at least three switches are off,


  • we know that the second and fourth switches are in the ON position.



 

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