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Answer:
It should be .5
Step-by-step explanation:
Okay so when there is 3 inches its 6 gallons and then when its 4 inches its 8 gallons. And so on. We only need the gallon to go up once so you just have to divide the inch by 2 because it goes from 6 gallons to 8 and we need 7. So halve an inch is .5.
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