A motorist paid $26.50 for 10 gallons of gas and 2 quarts of oil. Another motorist paid $23.58 for 8 gallons of gas and 3 quarts of oil. Find the cost of 1 gallon of gas and 1 quart of oil.
+23245 Let G represent the number of gallons of gas.
Let Q represent the number of quarts of oil.
10G + 2Q = 26.50 ---> multiply by 3 ---> 30G + 6Q = 79.50
8G + 3Q = 23.58 ---> multiply by -2 ---> -16G - 6Q = -47.16
Adding down the columns: 14G = 33.34
Dividing by 14: G = $2.31 (cost for 1 gallon of gas)
Substituting to find the amount of oil: 10G + 2Q = 26.50 ---> 10(2.31) + 2Q = 26.50 ---> 23.10 + 2Q = 26.50
Subtracting 23.10: 2Q = 3.40
Dividing by 2: Q = $1.70 (cost for 1 quart of oil)
