Use the image and table to answer the question.
An illustration shows a graph depicting cost of gasoline per gallon in dollars in store A. The horizontal axis shows gallons ranging from 0 to 20 in increments of 5. The vertical axis shows the cost in dollars ranging from 0 to 70 in increments of 10. Four data points are plotted on the graph at left parenthesis 0 comma 0 right parenthesis, left parenthesis 5 comma 20 right parenthesis, left parenthesis 10 comma 40 right parenthesis, and left parenthesis 15 comma 60 right parenthesis. A line connects all the data points.
Store B
Cost of Gasoline per Gallon
Gallons ($) Cost
5 18.75
10 37.50
15 56.25
The proportional relationships between the cost and the number of gallons of gasoline for Store A and Store B are displayed in the graph and table. Which store has the better buy for a gallon of gasoline? Enter 1 for Store A. Enter 2 for Store B.