Question

How can three resistors of resistance 2 ohm , 3 ohm and 5 ohm be connected to get a total resistance of (i)2.5 ohm (ii) 0.9 ohm

Answer 1

connect 2 ohm and 3 ohm in series then eq resistance = 5ohm now attach 5 ohm in parallel to get eq resistance as 2.5 ohm for case one.
for case two attach all three of the resistances in parallel to get 0.9 ohm as the eq resistance