Question

Find the equivalent resistance between A and B.

Answer 1

Equivalent resistance of $R_1$ and $R_2$ connected in parallel $R_{eq}=\frac{R_1{R}_2}{R_1+R_2}$
$6\Omega$ and $3\Omega$ resistors are connected in parallel.
Equivalent resistance of $6\Omega$ and $4\Omega$, $R_{6,3}=\frac{6\times 3}{6+3}=2\Omega$
$4\Omega$ and $12\Omega$ resistors are connected in parallel.
Equivalent resistance of $4\Omega$ and $12\Omega$, $R_{4,12}=\frac{4\times 12}{4+12}=3\Omega$
Now, $R_{6,3}$ and $R_{4,12}$ are connected in series.
Equivalent resistance between A and B $R_{AB}=R_{6,3}+R_{4,12}=2+3=5\Omega$