Southwest Regional First Aid Exam Taken from the 2019 Southwest Regional Mine Rescue Contest held in Ruidoso, New Mexico Progress Indicator: Question 5 of 30 5.  An AC circuit has 40-ohm R, 90-ohm XL, and 60-ohm XC, all in series.  The impedance equals: Choices: 50 ohms 70.7 ohms 110 ohms 190 ohms