Answer:
Cory bought 6.47 gallons
rate of change is $2.78 per gallon
Step-by-step explanation:
cost of gas per gallon = $2.78
it means that if one buy 1 gallon he will have to pay $2.78 and similary for each increase in 1 gallon of gallon gas he will have to pay $2.78.
Thus, rate of change is cost of gas per gallon as cost to buy gas changes with the change in quantity of gallon.
Let the quantity of gas bought be x gallon.
Total cost for x gallons = cost of gas per gallon*x = 2.78x
Given that total money paid by him is $18
2.78x = 18
x = 18/2.78 = 6.47
Thus, Cory bought 6.47 gallons
rate of change is $2.78 per gallon
