0.143 A
Explanation:
The total resistance of the circuit is
[tex]r = \frac{(40)(30)}{40 + 30} + \frac{(50)(20 + 10)}{50 + (20 + 10)} \\ = 35.89 \: ohms[/tex]
so the total current is
Itotal= V/R = 9V/35.89 ohms
= 0.25 A
To find the voltage drop across the 30-ohns resistor, use
V = Itotal × (combined resistance of 40 30)
= 0.25 A × 17.14 ohms = 4.285 volts
so the current through the 30-ohm resistor is
I = (voltage drop)/30-ohms
= (4.285 V)/(30 ohms)
= 0.143 A
