Answer :
First of all see the attachment for better understanding[tex].[/tex] :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
➝ Req = 3.6Ω
