Erin is buying produce at a store. she buys c cucumbers at $0.99 each and a apples at $0.79 each. what does the expression 0.99c+0.79a represent

The expression used in this question, 0.99c + 0.79a, is representative of the total cost of buying any number of apples and cucumbers, Where x = how many, 0.99c is the total cost of cucumbers when c is given as a value, and 0.79a is the total cost of apples when a is given as a value.