Find the supply voltage of a ladder circuit

[propvgvnda]

Then think again.
You have 7A in GH, 14A in FG. So what is the current in CG?
What is the current in DH and CD? So what is it in BC?

CG is 7A. I don't know how to calculate the current is DH and CD.

 

[epenguin]

You know the current in HG and you don't know the current in DH??!

KCL

From going very slowly this seems to be going backwards now.

It is not helped by not having labelled nodes in your figures.

You should also write the currents as they are calculated on the figures.

I said the solution should be obvious once you drew the diagrams. In fact the whole solution and its argument from start to finish could be written in a single sentence! You have said how the current splits at C. Do I need to repeat that it splits in the same way at B? That not merely the principle but in this case even the resistance values are the same at B Fig 3 as at C Fig 1? So if you know the current at HG you know the current at AB. You don't need any of the potentials up to this point. You end up with Fig 4 in which you know resistances and the current AB, and you have to calculate the overall voltage. Circuit problems don't come much easier than Fig 4.