Question

find the total resistance across A and B in the third part where all the resistances are of 1 Ohm.

Answer 1

Now the 3ohm resistance and 1ohm resistance are in parallel and their sum is in series with two 1ohm resistance.
So the answer is 10/3.
Hope this helped..

Answer 2

the resistors in CMA r in parallel
so net resisance is 3 ohm... so is in next arrangement
the last 2 resistors are in parallel so net resistance is 1/2 ohm
totla resistance is 3 + 3 + 0.5
6.5 ohm