A circuit consists of one DC power supply providing 20 V and four resistors R1 = 10 Ohm, R2 = 20 Ohm, R3 = R4 = 40 Ohm. R1, R2 and R3 are connected in series, whereas R4 is connected in parallel to R2. Calculate the total power provided by the power supply and the voltage drops through R1, R2 and R3.