The circuit in the figure is composed of two batteries (ε1 = 8 V and ε2 = 5 V) and four resistors (R1 = 110 Ω, R2 = 40 Ω,R3 = 40 Ω, and R4 = 50 Ω) as shown.
1) What is the current I1 which flows through R1?
2) What is the current I3 that flows through R3?