Ya as others said it uses very little. It wouldn't surprise me if you didn't even move off 3/4 full.
In our Class C on a 10 day trip using the hot water almost every night and the fridge running on gas at least 5 days I don't even think we used 1/2 of the tank. The real killer of the gas is the furnace. I think I have a 40lb capacity.
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