answer:

Assume the following circuit:

V = 4V

Total resistance in line 1 = R1 = 6 + 3 = 9 Ω

Total resistance in line 2 = R2 = 12 + 3 = 15 Ω

a) Current flowing through resistor 6 is equal to current flowing through line 1 = V/R1 = 4/9 = 0.44

b) The potential difference between lines 2 and 3 is 4V.

V/R2 = 4/15 (current through line 2)

Difference in potential across 12 resistors = (4/15) 12 = 3.2V