The equivalent resistance between the terminals A and D of the following circuit is:

$\begin {array} {1 1} (A)\;13 \: \Omega & \quad (B)\;18 \: \Omega \\ (C)\;10 \: \Omega & \quad (D)\;16 \: \Omega \end {array}$

Since terminals B and C are not connected, the two corresponding
5 $\Omega$ resistors are open circuited. Hence the equivalent circuit is as shown
Hence, the equivalent resistance is $5 + 5 + \Large\frac {(3+3)\times(3+3)} {(3+3)+(3+3)}$$= 13 \Omega$
Ans : (A)
edited Mar 24, 2014