The figure below shows a circuit powered by an ideal battery. The following values are given: R1 = 20?,R2 = 20?,R3 =30?,R4 =8?, ?=12V.
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(a) What is the current through the battery?
(b) What is the current through R2?
(c) What is the current through R3?
(d) Draw the equivalent circuit to the one given.