Rt = 170 OHMS.

To solve for the current through any resistor in

a circuit containing parallel circuits connected

in series, calculate the voltage across the

resistor, and then apply Ohm's law to determine

the current through the resistor.

Figure a

Figure b

The simplified diagram is used to determine the

voltage across each resistor. R3 and R4 are in

parallel, and the voltage across R4 is equal to

the voltage across R3. Since RB in the simplified

diagram represents the parallel combination of R3

and R4, the voltage across RB is equal to the

voltage across R3 and R4. Solving for the

voltage,

Rt = RA + RB = 150

It = Et

Rt

It = 300 v = 2 a

150