Three long parallel wires are 3.9cm from one another. (Looking along them, they are at three corners

Question:

Three long parallel wires are 3.9cm from one another. (Looking along them, they are at three corners of an equilateral triangle.) The current in each wire is 8.00A, but its direction in wire M is opposite to that in wires N and P (Fig. 20-60). Determine the magnetic force per unit length on each wire due to the other two.