Example of Voltage divider Rule

Firstly, I am explaining an example on VDR ( i.e. voltage divider rule ).
Determine voltage across R4 by voltage division rule. Assume V1 = 30V ,
 R1 =10 Ω , R2 =5Ω , R3 =10Ω , R4 = 5Ω

Solution:

          Here please note that you can not apply voltage division rule directly. That is
VR3 ≠   (R3/R1 + R3) V1 
Reason is that some current of R1 also passes through R2 and R3 so directly VDR cannot be applied. So to apply consider circuit as shown below

Now VR3  can be found  by VDR as
VR3 = (R3/R1 + R3) V1 

But that is not the orignal question so to find voltage across R4 by VDR we have to reduce our circuit as shown

R24 = 5Ω + 5Ω  = 10Ω
Now reduce the circuit further as

R324 = R3 // R24 = (10x10)/(10+10) = 5Ω
So now we can apply VDR to the above circuit
VR324 = ( R324/(R324 + R1) ) x V1 = 10V
Now this voltage applies on R324 and as in R324, R3 and R24 are in parallel so by VDR rule in parallel branch voltage remains same so
VR324 = VR24
Now VR24 is across R2 and R4. And we can see that R2 and R4 are in series so here by VDR rule voltage divides. So now VR4 can be found by VDR rule simply as
VR4 = ( R4/(R4 + R2) ) x VR24 = 5V
that is the desired solution.
This is a tricky example i guess but it explains much knowledge of voltage divider rule to you.I solved this example step by step along with figures for your better understanding.Hope you got my point now same thing i want to say again you should have to practice more problems on that rule for your better grip on basics of linear circuits analysis.
Now you are in a position to move on to current divider rule.

Hope you all understand it clearly if you face any problem regarding this contact me via comments.