A circuit has n inputs and n outputs. It is implemented only using AND, OR and NOT gates. Further, there are no fan-out branches. What is the number of s-a faults that remain after fault collapsing?
s-a means stuck at fault
Given the specified conditions, you can only have single input AND & OR gates so that each input flows to a single output. And assuming you really mean both s-a-0 and s-a-1, so 2*n faults.