Question

Just found this question. It makes me feel like crap.

Answer 1

http://i.imgur.com/cVePkNE.png

Answer 2

Alright, something looks like a Wheatstone bridge here. :)

Answer 3

@iambatman !!!

Answer 4

http://prntscr.com/3otn2w Found the solution to this. Can anyone explain how they reached here?

Answer 5

I feel your pain, the circuit gave me a headache. I fear I have over simplified by ignoring the two 25 Ohm resistors which appear to me to be in a balanced bridge (15/30 and 12/24), so this would be more or less a swag but I believe the resistance is 19.0 Ohms.

Answer 6

oh my GOODNESSS LOl

Answer 7

yup lol

Answer 8

Yup, erased those two already. Do I also combine the 30-30 and 24-24?

Answer 9

are we allowed to use calculator

Answer 10

id write huge matrices and just make the computer do it for me

Answer 11

I have a feeling that we are supposed to remove those diagonals too, since we're supposed to find the effective resistance between A and B, and those diagonals bring the current back from point B.

This gives me 23.5 Ohms, but I'm not sure. Olympiads consider every little element of our thinking.

Answer 12

have you tried using Y delta transforms

Answer 13

No, I'd rather use normal methods.

Answer 14

First I'd figure out all the places with the same potentials

Answer 15

put a test source at a and b, and write nodal equations

Answer 16

There's also symmetry so...phew that makes it a bit easier.

Answer 17

Yes, I'm more interested in the solution exploiting symmetry.

Answer 18

Yeah I assumed so :P

Answer 19

I don't want to draw it out..but I'd draw it out first haha, so it looks better

Answer 20

well you have to label all the stuff...lol, you can see though everything on the line with have the same potential.