A grocery store sells oranges for $1.50 per pound and grapes for $2.75 per pound. A customer buys pounds of oranges and pounds of grapes, and the total cost is $12.25. The equation represents this transaction. What does represent in the equation?
The total number of pounds of grapes
The total cost of the oranges, in dollars
The price of one pound of grapes, in dollars
The total cost of the purchase, in dollars
