Thanks Externet. The instructor is using the Seiman's Step2000 Basic electricity 1&2 book from the internet with his own notes and problems and homework and labs added in.
I have the parallel/series thing down, but I have a couple of formulas. Series is Σ1+Σ2+Σ3+Σn=Σt (Kirchoff voltage law)
Is the parallel formula (Kirchoff's Current Law)
1/R1+1/R2+1/R3+1/Rn=Rt
So if I have R1=5Ω, R2=10Ω and R3=20Ω then Rt=1/5+1/10+1/20...find the lowest common denominator which is 20 so 4/20+2/20+1/20=7/20=.35Ω
If 2 resistors are used then it is Rt=R1×R2/R1+R2
I think I have that part down. Now the instructor gives us the problem R1is a series resistor that feeds into a parallel circuit R2 and R3
R1=25.25Ω,R2=45Ω,R3=3.35Ω Σ=100V
So if I grasp the concept right then R1+R2×R3/R2+R3=Rt 25.25+45×3.35/25.25+3.25=25.25+150.75/28.5=30.539Ω
NOW to get the voltage drop I use Ohm's Law Σ=I×R SO I have to figure out the current first...I=Σ/Rt...I=100v/30.539Ω=3.274A
THEN 3.27A/30.529Ω=.107V
This answer doesn't look correct