Question

how can three resistors of resistance 2 3 and 6 ohms be connected to give total resistance of 4 ohm​

Answer 1

Let the resistances of values 3 and 6 be connected in parallel and that of 2 to be in series.

The equivalent resistance of the parallel connection will be :

1/3 + 1/6 = 1/r

r = 2.

The 2 ohms resistor will be in series to the equivalent resistance of 2 ohms.

So Rnet = 2 + 2 = 4 ohms.

Answer 2

1/R=1/6+1/3

=3/6

=1/2

R=2

now equivalent resistance =2+2

=4 ohm