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Anyway, this is a solved problem, but I can't get the answer :S

## Homework Statement

## Homework Equations

* Series-Parallel combination (RT=R1+R2+R3...+Rn for series, 1/RT=1/R1+1/R2+1/R3...+1/Rn for parallel)

* WYE (TEE) - DELTA (PI) Transformations:

1- WYE (TEE) to DELTA (PI): Each resistor in the DELTA (PI) is equal to the sum of all possible products of WYE (TEE) resistors taken two at a time, divided by the opposite WYE (TEE) resistor.

2- DELTA (PI) to WYE (TEE): Each resistor in the WYE (TEE) is equal to the product of the resistors in two adjacent DELTA (PI) branches, divided by the sum of all three DELTA (PI) resistors.

## The Attempt at a Solution

I've tried to solve using two methods above, and I've ended up with 27.14 ohm for the equivalent resistance with both methods. When I looked at the solution above, I saw that the line the two 20 ohms resistors was not ignored (I though that as long as there is not resistor in a line, it can be ignored), but instead it was assumed that there was a 0 ohm resistor.

so my questions are:

1- How does the current flows or divides in the circuit? does the current flow normally through any line even if there isn't any resistor in it?

2- Is this case the same for the following?

Thank you in advance.