Question

Show how would you connect 3 resistors, each of resistance 6ohm, so that the combination has a resistance of 9ohm and 4ohm?

Answer 1

Two 6 Ω resistors are connected in parallel. Their equivalent resistance will be The third 6 Ω resistor is in series with 3 Ω. Hence, the net resistance of the circuit is 6 Ω + 3 Ω = 9 Ω.
(ii) Two resistors in series  
 
Here Rs=6+6=12 Ω let third resistance R3=6 ΩTwo 6 Ω resistors are in series. Their equivalent resistance will be the sum 
∴ the total resistance is 4 Ω  .  

Answer 2

                                            ---R---
                                 |--------|         |------- |
                                 |          ---R---          R
                                 |------------V-----------|

Here it is 9 ohms


                                           |---R---|
                                 |--------|---R--|------- |
                                 |         |---R---|         |
                                 |------------V-----------|