Question

The diagram below shows part of a circuit: 

 

If this arrangement of three resistors was to be replaced by a single resistor, its resistance should be:
 
(a) 9 Ω
(b) 4 Ω
(c) 6 Ω
(d) 18 Ω

Answer 1

 (a) 9 Ώ
The two resistors of 6 Ώ are connected in parallel with each other. So, their net resistance 3 Ώ is connected in series with a resistance of 6 Ώ. So, the net resistance of the complete arrangement is 9 Ω.