Final answer:
In the prediction equation y=0.5x−6, the variable x represents the price at which each lemonade is sold. This is because x is multiplied by the number of lemonades to calculate the profit, implying it's a per-unit price rather than total revenue or costs.
Step-by-step explanation:
The prediction equation given is y = 0.5x - 6, where y represents the profit from selling lemonades. The question specifies that the profit is $7 when 25 lemonades are sold. To determine what the variable x represents, we need to consider what could logically be multiplied by the number of lemonades sold (which is 25 in this case) in order to calculate profit. Since x is multiplied directly by the number of lemonades, it does not represent the cost of making one lemonade, which would typically be subtracted, not multiplied. Neither does it represent the total revenue as total revenue would equate to the number of lemonades sold times the price of each lemonade. Therefore, by process of elimination and understanding the context of the problem, x represents the price at which each lemonade is sold (option d).