In the circuit shown in figure, the current through the given resistor is 
Step 1: The circuit is a ladder network with identical vertical resistors connected at equal intervals.
Step 2: Using symmetry and series–parallel reduction, equivalent resistances of successive sections can be evaluated.
Step 3: Applying Ohm’s law after reduction of the network gives the current through the 3Ω resistor as: I = 0.25A