The amount of money it takes to fill up a gas tank varies directly with the number of gallons bought. it cost $21.87 to fill up a car with gasoline with 9 gallons of gasoline. what is the constant of variation?

$2.43 per gallon of gas.

Step-by-step explanation:

We have been given that the amount of money it takes to fill up a gas tank varies directly with the number of gallons bought.

We know that the equation for two directly proportional quantities is in form: , where,

k = The constant of variation and y is directly proportional to x.

To find the constant of variation for our given equation, we will substitute the given values in above equation as:

Let us divide both sides of our equation by 9 gallons.

Therefore, the constant of variation is $2.43 per gallon of gas.

no solution

step-by-step explanation:

there is not enough information in the problem to solve.