mohon dibantu, disertakan jg caranya yaa.. terimakasih:)

diket :
Vp = 220 v
Vs = 55 v
Ip =0,5 A
Is = 1,5 A
dit : efisiensi
jwb :
ef = ( Is . Vp / Ip . Vp ) . 100%
ef = ( 1,5 . 55 / 0,5 . 220 ). 100%
ef = ( 82,5 / 110 ) . 100%
ef = 75 %