y = 3.19x
y = 3.19(18.5)
y = 59.015
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Divide the total cost to the number of gallons bought to get the unit price of each gallon.
41.47 ÷ 13 gallons = 3.19 per gallon.
y = 3.19x
Where x corresponds to the number of gallons bought.
If x = 18.50 gallons.then,
y = 3.19(18.50)
y = 59.015