How to find the total resistance, current going through, and the total energy used

Answer:
Explanation:
a) Re = 2 + (1/(1/3 + 1/1)) + 4 = 6¾ Ω
b) Current supplied by battery = 18 / 6¾ = 2⅔ A
Voltage across the 3 Ω resistor = 18 - 2⅔(2 + 4) = 2V
I₃ = 2 V /3 Ω = ⅔A
c) A Watt is 1 J/s
E = 18 V(2⅔ A)(2 hr)(3600 s/hr) = 345,600 J