This is an easy task.
For all series-parallel circuits do the parallel portion first. This effectively turns the parallel portion into a series portion or turns many resistors into one with a corresponding resistance value.
Once you have this then you can plug the values into Ohm's law and figure out the rest of the circuit.
Parallel: Total = 1/R1 + 1/R2 + 1/R3 + .... 1/Rn
Series: Total = R1 + R2 + R3 + ... + Rn
Ohm's law: E = IR - E = voltage, I = amperage, R = resistance
I highly recommend RIEP charts (P(ower)=I * E) to figure circuits out. You can implement this in code as well. Using RIEP charts you can figure out any circuit with little trouble.
Most of that question is a 'trick' question. Regardless of how the resistors in a circuit are arranged they always follow the fundamental parallel or series rules. If you have parallel portions, you must figure those out first.
Also remember this:
Series
Amperage is constant - hence you get voltage drops across the resistors
Parallel
Voltage is constant - hence you can figure out how many amps are flowing through each resistor in a parallel circuit
