R1 = 30 ohm, R2 = 60 ohm,dan R3 = 20 ohm

a. 45 Ω

b. 0,1 A

Penjelasan dengan langkah-langkah:

Rp di saluran paralel

1/Rp = 1/20 + 1/60

= 3/60 + 1/60

= 4/60

Rp = 60/4 = 15 Ω

a. RT = R1 + Rp

= 30 + 15

= 45 Ω

b. I = V : R

= 4,5 : 45

= 0,1 A