KCET 2018 Physics Solved Paper

The two 3 Ω resistance are in series, therefore their equivalent resistance = 6 Ω
Thus, the network reduces to the circuit as follows:Now, the two 6 Ω resistance are in parallel, therefore their equivalent resistance = 3 Ω
Thus, the network reduces to the circuit as follows :Now, all the resistance are in series therefore their equivalent resistance = 12 Ω
Therefore, effective resistance between P and Q is 12 Ω.