Question

Find the equivalent resistance between points $A$ and $B$.

Answer 1

$12\Omega ,6\Omega$ and $4\Omega$ are in parallel.
Hence, $\frac{1}{R_p}=\frac{1}{4}+\frac{1}{6}+\frac{1}{12}$ $=\frac{3+2+1}{12}=\frac{1}{2}$
$R_p=2\Omega$
Now $2\Omega$, $R_p$ and $5\Omega$ are in series.
Therefore, $R_{AB}=2+2+5$$=9\Omega$