For the network shown in the figure, the value of the current i is

The circuit given resembles the balanced Wheatstone bridge as 46 =23Thus, middle anm containing 4  Ω resistance will be ineffective and no current flows through it.The equivalent circuit is shown as below:Net resistance of AB and BC,R'=4+2=6  ΩNet resistance of AD and DC,R''=6+3=9  ΩThus, parallel combination of R' and R" givesR=  R' × R'' R' + R''  =  6  ×  96+9  =  5415  =  185  ΩHence, current  i=VR=V18/5  =5V18