Equivalent resistance between A and B.
A) 2.4 ohms
B)18 ohms
C) 6 ohms
D) 36 ohms

First of all see the attachment for better understanding :D

Eq. resistance between C and D :

➝ 1/Rp = 1/6 + 1/6

➝ 1/Rp = 2/6

➝ Rp = 3Ω

Eq. resistance of upper part :

(All three are in series)

➝ Rs = 3 + 3 + 3

➝ Rs = 9Ω

Eq. resistance of lower part :

(Both are in series)

➝ Rs' = 3 + 3

➝ Rs' = 6Ω

Eq. resistance between A and B :

(Rs and Rs' are in parallel)

➝ 1/Req = 1/Rs + 1/Rs'

➝ 1/Req = 1/9 + 1/6

➝ 1/Req = (2 + 3)/18

➝ Req = 18/5

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