Among 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 times 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?