Among the five objects, Gas stove, Washing machine, Refrigerator, Inverter and Microwave oven:

the Washing machine is twice as heavy as the Inverter;

the Gas stove is one and half time as heavy as the Microwave oven;

the Washing machine and Microwave oven together weigh as much as the Gas stove and Inverter together;

the Refrigerator and Inverter together are one and half times as heavy as the Gas stove.

Which is the heaviest among the five objects?