Answer: First option
Step-by-step explanation:
By definition Direct variation equations have the following form:
[tex]y=kx[/tex]
Where "k" is the constant of variation.
Let be "c" the total cost of gasoline and "g" the number of gallons purchased.
You know that the total cost of gasoline varies directly with the number of gallons purchased and the cost of the gas per gallon is $1.89.
You can identify that the constant of variation in this situation is:
[tex]k=1.89[/tex]
Therefore, based on this, you can write the following Direct variation equation to model the total cost for gallons of gas:
[tex]c=1.89g[/tex]
