Question

Show how would you join three resistors, each of resistance 9 ohms so that the equivalent resistance of the combination is.

(1). 13.5 ohms (2). 6 ohms ?

Answer 1

 1: Three 9Ω resistors are in parallel connection.

INV((1/9) + (1/9) + (1/9)) = 3Ω

possibility 2: Two 9Ω resistors are in parallel with one 9Ω in series connection.

INV((1/9) + (1/9)) + 9 = 13.5Ω

possibility 3: Two 9Ω resistors are in series with one 9Ω in parallel connection.

INV((1/(9+9)) + (1/9)) = 6Ω

possibility 4: Three 9Ω are in series connection.

9+9+9 = 27Ω

So, in no way we can get a equivalent of 12Ω 

Answer 2

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Hope this helps u!