(1)150×0.52=78(元)(2)150÷(1+)×0.55=150÷5 3 ×0.55=49.5(元)150÷(1+)××0.35=150÷5 3 ××0.35=21(元)49.5+21=70.5(元)70.5<78答:安装分时电表节省电费.