math
posted by Anonymous .
Ez stop fast gas sold 10957 worth of gasoline yesterday. Redular grade sold for 2.30 a gallon and premium grade sold for 2.55 a gallon. If the station sold 420 more regular than premium, how many gallons of regular were sold

Represent the unknown with variables:
Let x = amount of premium grade gasoline sold in gallons
Let x+420 = amount of regular grade gasoline sold in gallons (according to the third statement)
Then we set up the equation. We know that the total worth of gasoline sold is 10,957. Therefore, we multiply the costs per each gallon of regular & premium grade by their respective amounts and get the total:
2.55x + (2.30)(x+420) = 10957
Solving for x,
2.55 + 2.3x + 966 = 10957
4.85x = 10957  966
4.85x = 9991
x = 2060 gallons of premium grade, and
x+420 = 2480 gallons of regular grade
Hope this helps~ :) 
gbjgv

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