A 3 phase, 2 winding, 230kv/115kV, delta-wye, 50MVAtransformer has a series impedance of (4.0 at angle 81 degrees) %and core losses of 1.0% at rated voltage. When the transformer issupplying a load of 40MW at a power factor of 0.80 lagging at ratedvoltage, determine the percent efficiency and the percent voltage regulation.