Three long wires (wire $1,$ wire $2,$ and wire 3 ) hang vertically. The distance between wire 1 and wire 2 is $20.0 \mathrm{cm} .$ On the left, wire 1 carries an upward current of 1.50 $\mathrm{A}$ . To the right, wire 2 carries a downward current of 4.00 $\mathrm{A}$ . Wire 3 is located such that when it carries a certain current, each wire experiences no net force. Find (a) the position of wire $3,$ and $(b)$ the magnitude and direction of the current in wire 3 .