Question

Jessica decides to mix grades of gasoline in her truck. She puts in 8 gallons of regular and 8 gallons of premium for a total cost of $41.04. If premium gasoline costs $0.21 more per gallon than regular, what was the price of each grade of gasoline?

Answer 1

The price of the regular gasoline is $2.46, while the premium is $2.67.

Explanation:

Let the price of regular gasoline be "x", while the price for the premium be "y", The sum of the amount of each type of gas multiplied by its cost should be equal to the total paid, therefore:

`8*x + 8*y = 41.04`

We also know that the premium gas costs 0.21 more than the regular one, therefore:

`y = x + 0.21`

We can apply the second expression on the first, in order to solve for "x".

`8*x + 8*(x + 0.21) = 41.04\\8*x + 8*x + 1.68 = 41.04\\16*x = 41.04 - 1.68\\16*x = 39.36\\x = (39.36)/(16) = 2.46`

`y = 2.46 + 0.21 = 2.67`

The price of the regular gasoline is $2.46, while the premium is $2.67.