In this circuit voltage of battery is 9v,and two resistors 5 ohm ,10 ohm are connected in seriesNow we have to find total current in the circuitAccording to ohm's lawV = total voltage, R = total resistance ,I = total current in a circuitNow we have to find total resistanceR = 5 +10 = 15 ohmSince 2 resistors are in series the total resistance R = R1 + R2