Two paralle wires carrying current I is the same direction atttract. The force on each wire is equal and opposite .
Two parallel wires carrying current I in the opposite direction repel . The force on each wire are equal and opposite.
This is an example of action reaction pair.
Two parallel wires carrying current I and 2I in the same /opp direction attract /repel . The force one each wire is equal and opposite. This can easily be explained using F=BIL. The force F on wire = (2B)IL = B(2I)L . The magnetic of wire carrying 2I is twice the magnitude and hence 2B.
