Circuits Answers

1) 2 A

2) 22 A through battery
   12 A, 6 A, 4 A through resistors

3) 60/11 A through upper branch
   24/11 A through middle branch
   36/11 A through lower branch

4) switch open:
     4 A through battery
     4 A through middle branch
     0 A through lower branch
   switch closed:
     7 A through battery
     4 A through middle branch
     3 A through lower branch

5) switch open:
     12/5 A through battery
     12/5 A through middle branch
     0 A through lower branch
   switch closed:
     42/13 A through battery
     24/13 A through middle branch
     18/13 A through lower branch

6) switch open:
     12/7 A through battery
     6/7 A through each branch
     12/7 A through 4 Ωresistor
   switch closed:
     24/11 A through battery
     6/11 A through 6 Ωresistor
     0 A through 3 Ωresistor
     18/11 A through 2 Ωresistor
     24/11 A through 4 Ωresistor

7) 20 A through lower battery
   16 A through side battery
   8 A, 8 A, and 4 A through resistors 

8) 4 A through lower battery and lowest resistor
   no current anywhere else!

9) 24/11 A through battery
   12/11 A each through left-side branches
   8/11 A, 4/11 A, 4/11 A, and 8/11 A through lower branches
   24/11 A through lone right-side resistor